'Superman' actress Margot Kidder dies at 69

Margot Kidder, who famously played Lois Lane opposite Christopher Reeve in 1978's "Superman," died on Sunday at the age of 69.

The actress passed away at her home in Montana, a spokesperson at Franzen-Davis funeral home in Livingston, Montana, confirmed to TMZ on Monday. Her cause of death is unknown at this point.

Kidder went on to portray her iconic character in the film's three sequels "Superman II," "Superman III" and "Superman IV: The Quest for Peace" and continued acting in the decades since her breakout role.

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The Canadian actress also appeared in "The Amityville Horror," "Black Christmas" and TV series "Boston Common." She won an Emmy for her performance on children's show "R.L. Stine's The Haunting Hour" and appeared in the Broadway production of "The Vagina Monologues" in 2002.

See photos of Margot Kidder:

39 PHOTOS
'Superman' actress Margot Kidder throughout her career
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'Superman' actress Margot Kidder throughout her career
Portrait of actress Margot Kidder. (Photo by Herbert Dorfman/Corbis via Getty Images)
Christopher Reeve as Superman (left) and as Clark Kent (right) with Lois Lane, played by Margot Kidder, in the 1978 film Superman: The Movie.
NICHOLS -- 'Nichols' Episode 101 -- Pictured: Margot Kidder as Ruth -- (Photo by: Gary Null/NBC/NBCU Photo Bank via Getty Images)
ABC MOVIE FOR TV - 'The Bounty Man' - Airdate: October 31, 1972. (Photo by ABC Photo Archives/ABC via Getty Images) JOHN ERICSON;MARGOT KIDDER
Margot Kidder relaxing on the couch in a scene from the film 'Sisters', 1973. (Photo by American International Pictures/Getty Images)
CANADA - APRIL 17: Margot Kidder; who was born in Vancouver; has just finished filming The Geat Waldo Pepper; which stars Robert Redford. The 25-year-old actress is in Toronto to shoot a horror flick; Black Christmas. (Photo by Dick Darrell/Toronto Star via Getty Images)
UNITED STATES - JULY 07: Christopher Reeve and Margot Kidder filming 'Superman' at the New York Daily News building at 220 E. 42nd St. (Photo by Harry Hamburg/NY Daily News Archive via Getty Images)
UNITED STATES - JULY 07: Christopher Reeve and Margot Kidder during filming of 'Superman' on 42nd St.. (Photo by Harry Hamburg/NY Daily News Archive via Getty Images)
WASHINGTON,DC. - DECEMBER 10: Actress Margot Kidder attends the Presidential Premiere of 'Superman' on December 10, 1978 at Eisenhower Theater at the John F. Kennedy Center for the Performing Arts in Washington, DC. (Photo by Ron Galella/WireImage)
Christopher Reeve and Margot Kidder at the JFK Center for the Performing Arts, Eisenhower Theater in Washington, D.C., (Photo by Ron Galella/WireImage)
Margot Kidder and Christopher Reeve (Photo by Ron Galella/WireImage)
LOS ANGELES, CA - CIRCA 1979: Christopher Reeve, Margot Kidder and Giorgio Moroder circa 1979 in Los Angeles, California. (Photo by Bret Lundberg/IMAGES/Getty Images)
BEVERLY HILLS,CA - MARCH 7: Actress Margot Kidder attends the Seventh Annual American Film Institute Lifetime Achievement Award Salute to Alfred Hitchcock on March 7, 1979 at Beverly Hilton Hotel in Beverly Hills, California. (Photo by Ron Galella/WireImage)
Margot Kidder and Christopher Reeve during 51st Annual Academy Awards at Dorothy Chandler Pavilion at the L.A. Music Center in Los Angeles, CA, United States. (Photo by Ron Galella/WireImage)
UNITED STATES - circa 1980: Actress Margot Kidder. (Photo by The LIFE Picture Collection/Getty Images)
NEW YORK - AUGUST 1: Margot Kidder poses for a candid photo August 1, 1980 in New York City while campaigning for John Anderson for President. (Photo by Yvonne Hemsey/Getty Images)
NEW YORK CITY - AUGUST 12: Margot Kidder attends Democratic Fundraising Benefit Party for Mark Green on August 12, 1980 at the Empire State Building in New York City. (Photo by Ron Galella, Ltd./WireImage)
Actress Margot Kidder, wearing pink gown w. white accents, in Press Room at Academy Awards. (Photo by John Paschal/DMI/The LIFE Picture Collection/Getty Images)
THE 55TH ANNUAL ACADEMY AWARDS - Broadcast Coverage - Airdate: April 11, 1983. (Photo by ABC Photo Archives/ABC via Getty Images) MARGOT KIDDER AND WILLIAM SHATNER, PRESENTERS BEST ART DIRECTION
Margot Kidder sur le tournage du film 'Louisiane' r�lis�par Philippe de Broca en mai 1983 aux Etats-Unis. (Photo by Micheline PELLETIER/Gamma-Rapho via Getty Images)
LOS ANGELES - 1985: Actress Margot Kidder poses for a portrait in 1985 in Los Angeles, California. (Photo by Harry Langdon/Getty Images)
NEW YORK CITY - APRIL 28: Actress Margot Kidder attends the 'Command Performance Benefit for the Millay Colony for the Arts' on April 28, 1986 at St. Regis Hotel in New York City, New York. (Photo by Ron Galella, Ltd./WireImage)
NEW YORK CITY - JULY 7: Musician Steve Jordan and Actress Margot Kidder attend the New York City Premiere of 'A Fish Called Wanda' on July 7, 1988 at Walter Reade Auditorium at Lincoln Center in New York City, New York. (Photo by Ron Galella, Ltd./WireImage)
NEW YORK CITY - NOVEMBER 28: Actress Margot Kidder attends the Third Annual Better World Society Gala on November 28, 1988 at Waldorf-Astoria Hotel in New York City, New York. (Photo by Ron Galella, Ltd./WireImage)
NEW YORK CITY - JUNE 25: Actress Margot Kidder attends the New York Women in Film's Third Annual Softball Game on June 25, 1990 at Heckscher Playground at Central Park in New York City, New York. (Photo by Ron Galella, Ltd./WireImage)
LOS ANGELES - JULY 13: Actress Margot Kidder attends the 'National Cable Forum Press Tour' on July 13, 1990 at Century Plaza Hotel in Los Angeles, California. (Photo by Ron Galella, Ltd/WireImage)
NEW YORK CITY - OCTOBER 21: Actress Margot Kidder attends the 'Walden Woods Project Benefit Concert - After Party' on October 21, 1991 at Tavern on the Green in New York City, New York. (Photo by Ron Galella, Ltd./WireImage)
THE TONIGHT SHOW WITH JAY LENO -- Episode 1031 -- Pictured: (l-r) Actress Margot Kidder with host Jay Leno during an interviewon November 14, 1996 -- (Photo by: Margaret Norton/NBC/NBCU Photo Bank via Getty Images)
Story is about Margot Kidder and how her life with mental illness. She is in LA to promote a new mental health film. 023087.SO.0118.kidder.2 Margot Kidder at the Universal Sheraton Hotel in Universal City. (Photo by Annie Wells/Los Angeles Times via Getty Images)
Margot Kidder at the Beverly Garland Holiday Inn in Hollywood, California (Photo by Victor Spinelli/WireImage)
Superman's 'Lois Lane', Margot Kidder at the Venue: Donald E. Stephens Convention Center in Chicago, Illinois (Photo by Barry Brecheisen/WireImage)
Margot Kidder and Richard Donner at the The Director's Guild Theater in West Hollywood, CA (Photo by Albert L. Ortega/WireImage)
UNITED STATES - MARCH 01: BROTHERS & SISTERS - 'Three Parties' - Nora's romantic life takes an upturn when her troublemaking friend (guest starring Margot Kidder as Emily Craft) convinces her to take a chance with her professor (guest starring Peter Coyote as Mark August). Meanwhile, Chad comes to terms with his sexuality at Kevin's expense and Justin steps up to protect his half-sister, on 'Brothers & Sisters,' SUNDAY, APRIL 8 (10:01-11:00 p.m., ET), on the ABC Television Network. (Photo by Gale Adler/ABC via Getty Images)
HOLLYWOOD - AUGUST 24: Actress Margot Kidder arrives at the premiere of Dimension Films' 'Halloween II' held at Grauman's Chinese Theater on August 24, 2009 in Hollywood, California. (Photo by Alberto E. Rodriguez/Getty Images)
August 9, 2010-MARGOT KIDDER-Iconic actress Margot Kidder, poses for a photo Monday August 9, 2010 inside of Toronto's Panasonic Threatre. Kidder is in Toronto to star in 'Love, Loss and What I Wore' an intimate collection of stories by Nora Ephron and Delia Ephron, based on a book by Ilene Beckerman. Toronto Star/Tara Walton (Photo by Tara Walton/Toronto Star via Getty Images)
PHILADELPHIA, PA - JUNE 18: Actress Margot Kidder attends Wizard World's Philadelphia Comic Con 2011 at the Pennsylvania Convention Center on June 18, 2011 in Philadelphia, Pennsylvania. (Photo by Gilbert Carrasquillo/FilmMagic)
ANAHEIM, CA - APRIL 04: Actress Margot Kidder attends day 2 of WonderCon Anaheim 2015 held at Anaheim Convention Center on April 4, 2015 in Anaheim, California. (Photo by Albert L. Ortega/Getty Images)
ANAHEIM, CA - APRIL 04: Actress Margot Kidder attends day 2 of WonderCon Anaheim 2015 held at Anaheim Convention Center on April 4, 2015 in Anaheim, California. (Photo by Albert L. Ortega/Getty Images)
ANAHEIM, CA - APRIL 04: Actress Margot Kidder, Diane Sherry, Marc McClure, Valerie Perrine and Aaron Smolinski attend day 2 of WonderCon Anaheim 2015 held at Anaheim Convention Center on April 4, 2015 in Anaheim, California. (Photo by Albert L. Ortega/Getty Images)
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Kidder suffered a widely-publicized manic breakdown in April of 1996, which led to her being diagnosed with bipolar disorder. After a computer virus caused her to permanently lose years worth of drafts of her autobiography, Kidder disappeared for days before being found in a distressed state after reportedly being raped. She was placed in psychiatric care and later said in 2007 that she hadn't had a serious manic episode in over a decade.

As TMZ notes, she also became an outspoken advocate for mental health in the later part of her life.

The actress was married and divorced three times and shared her only daughter, Maggie McGaune, with first husband, novelist Thomas McGuane. She was also romantically connected with Steven Spielberg, former Canadian prime minister Pierre Trudeau (father to current PM Justin Trudeau) and Richard Pryor.

Celebrities who have died in 2018:

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Celebrities who died in 2018
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Celebrities who died in 2018

Aretha Franklin died at the age of 76 on August 16 following a long battle with cancer. Read more here.

(Photo by Ron Galella, Ltd./WireImage)

Renowned celebrity chef Anthony Bourdain died of an apparent suicide on June 8. Read more here.

(Photo: Reuters)

"Superman" actress Margot Kidder died at the age of 69 in May. Read more here.

(Photo by Gilbert Carrasquillo/FilmMagic)

Burt Reynolds died at the age of 82 on September 6 after going into cardiac arrest. Read more here.

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Comic book legend Stan Lee died at the age of 95 in early November. Read more here.

(Photo by Jon Kopaloff/FilmMagic)

Designer Kate Spade died on June 5, 2018 by suicide. Read more here.

(Photo: Getty)

DJ Avicii died at 28 on April 20. Read more here.

(Photo by Christopher Polk/Getty Images for MasterCard)

Rapper Mac Miller died at the age of 26 on September 7 following an accidental drug overdose. Read more here.

(Photo by Scott Kowalchyk/CBS via Getty Images)

Joe Jackson died at the age of 89 at the end of June. Read more here.

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Kim Porter, Diddy's ex and the mother of three of his children, died suddenly in November at the age of 47. Read more here.

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"Austin Powers" actor Verne Troyer died at 49 on April 21. Read more here.

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"Damn Yankees" star and gay icon Tab Hunter died at the age of 86 from cardiac arrest on July 7. Read more here.

(Photo by Silver Screen Collection/Getty Images)

The Cranberries lead singer Dolores O'Riordan died at 46 on January 15. Read more here

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"The Facts of Life" star Charlotte Rae died at the age of 92 in early August. Read more here.

(Photo by NBC/NBCU Photo Bank via Getty Images)

"Frasier" star John Mahoney died at 77 on February 4. Read more here.

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Former "Glee" actor Mark Salling died at 35 on January 30. Read more here.

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Rapper XXXTentacion was shot dead at the age of 20 on June 19. Read more here.

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Former child star Jon Paul Steuer (right) died on January 1 at the age of 33. Read more here.

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"Ladies of London" star and model Annabelle Neilson was found dead at the age of 49 in mid-July. Read more here.

(Photo by David M. Benett/Dave Benett/Getty Images for Claridge's)

"Hee Haw" host and country music legend Roy Clark died in November at the age of 85. Read more here.

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Comedian Marty Allen died at 95 on February 12. Read more here.

(Photo by Ethan Miller/Getty Images)

Actor Jerry Van Dyke died on January 5 at age 86. Read more here.

(Photo by Mitch Haddad/ABC via Getty Images)

Richard "Old Man" Harrison from "Pawn Stars died on June 25 at the age of 77. Read more here.

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Moody Blues co-founder Ray Thomas died on January 7 at 76. Read more here.

(Photo by Jim Steinfeldt/Michael Ochs Archives/Getty Images)

Motorhead guitarist "Fast" Eddie Clarke died at 67 on January 10. Read more here.

(Photo by Fin Costello/Redferns)

Original Mouseketeer Doreen Tracey died at 74 on January 10. Read more here.

(Photo by Ron Galella/WireImage)

Bobby Zarin (left), husband of former "Real Housewives of New York" star Jill Zarin, died at 71 on January 13. Read more here.

(Photo by Gonzalo Marroquin/Patrick McMullan via Getty Images)

Nancy Sinatra died at the age of 101 in mid-July. Read more here.

(Photo by Central Press/Hulton Archive/Getty Images)

"General Hospital" star Susan Brown died on August 31 at the age of 86 after a battle with Alzheimer's. Read more here.

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Country singer Lari White died at 52 on January 23. Read more here.

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"Storm Chasers" star Joel Taylor died at the age of 38. Read more here.

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Former NBA star Rasual Butler and former "American Idol" contestant Leah LaBelle died in a car crash on January 30. Read more here.

(Photo by Paul Zimmerman/WireImage)

The Temptations vocalist, Dennis Edwards (center), died at 74 on February 2. Read more here.

(Photo by Paul Redmond/WireImage)

"Home Improvement" actor Mickey Jones died at 76 on February 7. Read more here.

(Photo by ABC Photo Archives/ABC via Getty Images)

Actor Reg E. Cathey died at 59 in February. Read more here.

(Photo by Bruce Glikas/Getty Images)

Former E! reality star Lyric McHenry was found at the age of 26 on August 14. Read more here.

Country singer Daryle Singletary died at 46 in early February. Read more here.

(Photo by Mindy Small/FilmMagic)

TV star Nanette Fabray died at 97 on February 22. Read more here.

(Photo by John Shearer/WireImage)

Bollywood actress Sridevi Kapoor died in late February at 54. Read more here.

(Photo by Amlan Dutta/Hindustan Times via Getty Images)

"MASH" star David Ogden Stiers died on March 3 at 75. Read more here.

(Photo by Tibrina Hobson/FilmMagic)

Rapper Craig Mack died at 46 on March 12. Read more here.

(Photo by Johnny Nunez/WireImage)

Singer and "The Voice" contestant Beverly McClellan died at the age of 49 in October following a long battle with cancer. Read more here.

(Photo by: Justin Lubin/NBC/NBCU Photo Bank via Getty Images)

Former child star Donna Butterworth died at 62 in March. Read more here.

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Frank Avruch (aka Bozo The Clown) died at 89 in March. Read more here.

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"Chicago Fire" actress Dushon Brown died at 49 on March 23. Read more here.

(Photo by Timothy Hiatt/Getty Images)

K-Pop singer Seo Min-woo died on March 25 at 33. Read more here.

Actress Susan Anspach died in April at 75. Read more here.

(Photo by Ron Galella, Ltd./WireImage)

Kids' TV host Chuck McCann died at 83 on April 8. Read more here.

(Photo by gotpap/Bauer-Griffin/GC Images)

"One Flew Over The Kuckoo's Nest" director Milos Forman died at 86 on April 13. Read more here.

(Photo by Ernesto Ruscio/Getty Images)

"Full Metal Jacket" actor R. Lee Ermey died at 74 on April 15. Read more here.

(Photo by Ethan Miller/Getty Images)

"Night Court" actor Harry Anderson died at 65 on April 16. Read more here.

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Country musician and song-writer Randy Scruggs died at 64 on April 17. Read more here.

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"Twin Peaks: Fire Walk With Me" actress Pamela Gidley died at 52 in April. Read more here.

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Dennis Shields, "Real Housewives of New York" star Bethenny Frankel's on-and-off boyfriend, died of an overdose on August 10. Read more here.

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Longtime "Days of Our Lives" star Peggy McCay died at the age of 90 of natural causes in October. Read more here.

(Photo by: Paul Drinkwater/NBC/NBCU Photo Bank via Getty Images)

"The Goldbergs" actor Jackson Odell died on June 8 at the age of 20. Read more here.

(Photo by Alberto E. Rodriguez/Getty Images)

LFO group member Devin Lima died in November at the age of 41 following a battle with cancer. Read more here.

(Photo by Derek Bauer/FilmMagic)

"Sons of Anarchy" actor Alan O'Neill died at the age of 47 in early June. Read more here.

(Photo by Amy Graves/Wireimage)

"Days of Our Lives" actor Frank Parker died at the end of September the age of 79 from complications of Parkinson's disease and dementia. Read more here.

(Photo by Vivien Killilea/Getty Images for Days Of Our lives)

Former "America's Got Talent" winner Neal Boyd died at the age of 42 in June. Read more here.

(Photo by Virginia Sherwood/NBC/NBCU Photo Bank via Getty Images)

Jerry Marren, the last living actor who played a munchkin in "The Wizard of Oz," died in June at the age of 98. Read more here.

(Photo by John M. Heller/FilmMagic)

"Spongebob Squarepants" creator Stephen Hillenburg died at the age of 57 from ALS. Read more here.

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Actor Robert Mandan died at the age of 86 in early June. Read more here.

(Photo by Malcolm Ali/WireImage)

Hugh Dane, who played Hank the security guard on "The Office," died in June at the age of 75. Read more here.

(Photo by Mitch Haddad/NBC/NBCU Photo Bank via Getty Images)

Jerry Maren, the last-living "Wizard of Oz" munchkin, died at the age of 98 in early June. Read more here.

(Photo by John M. Heller/FilmMagic)

Founding member of The Bay City Rollers, Alan Longmuir, died at the age of 70 at the beginning of July after a brief illness. Read more here.

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Former "ER" actress Vanessa Marquez was shot by police at the end of August. She was 49. Read more here.

(Credit: Alice S. Hall/NBCU Photo Bank)

Jefferson Airplane founding member Marty Balin died at the end of September at the age of 76. Read more here.

(Photo by Steve Granitz/WireImage)

Dennis Hof, owner of Moonlite Bunny Ranch, died at the age of 72 in October. Read more here.

(Photo by Bobby Bank/Getty Images)

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