'Rob & Big' star Christopher 'Big Black' Boykin dead at age 45

Christopher "Big Black" Boykin has died at the age of 45.

The former star of MTV's hit reality show "Rob & Big" passed away on Tuesday morning and, though there's no official cause of death yet, people close to the late star have reason to believe that Boykin died of a heart attack, TMZ reported.

SEE ALSO: MTV reality star Clay Adler commits suicide at 27

Boykin, who served in the Navy before starring on the show, became famous by getting into mischief and hilariously random adventures with co-star Rob Dyrdek, for whom he served as a bodyguard. Their unlikely friendship was the subject of "Rob & Big" for three seasons that ran from 2006 through 2008. They also starred on "Fantasy Factory" together.

See photos of Christopher "Big Black" Boykin:

25 PHOTOS
Christopher 'Big Black' Boykin throughout his life
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Christopher 'Big Black' Boykin throughout his life
NEW YORK - NOVEMBER 02: (U.S. TABS OUT) (L-R) Skater Rob Dyrdek and Christopher ?Big Black? Boykin from the show Rob & Big make an appearance on MTV's Total Request Live on November 2, 2006 in New York City. (Photo by Peter Kramer/Getty Images)
NEW YORK - NOVEMBER 02: (U.S. TABS OUT) (L-R) Skater Rob Dyrdek, Christopher ?Big Black? Boykin from the show Rob & Big and MTV VJ Damien Fahey make an appearance on MTV's Total Request Live on November 2, 2006 in New York City. (Photo by Peter Kramer/Getty Images)
Rob Dyrdek and Christopher Boykin (Photo by Jason Kempin/FilmMagic)
BURBANK, CA - NOVEMBER 30: Skater Rob Dyrdek (L) and Christopher 'Big Black' Boykin from the show Rob & Bigarrives at the Inagural 'Arby's Action Sports Awards' held at Center Staging on November 30, 2006 in Burbank, California. (Photo by Frederick M. Brown/Getty Images)
'Big Black' Christopher Boykin and Rob Dyrdek (Photo by Rebecca Sapp/WireImage for Arby�s Restaurant Group, Inc.)
Big Black Christopher Boykin and Rob Dyrdek during Inaugural Arby's Action Sports Awards - Red Carpet and Show at Center Staging in Burbank, California, United States. (Photo by Rebecca Sapp/WireImage for Arby�s Restaurant Group, Inc.)
BEVERLY HILLS, CA - OCTOBER 11: Actor Christopher 'Big Black' Boykin arrives to the 'Tony Hawk: Ride Presents Stand Up For Skateparks' benefit press conference held at the Green Acres Estate on October 11, 2009 in Beverly Hills, California. (Photo by Angela Weiss/FilmMagic)
BEVERLY HILLS, CA - OCTOBER 17: TV personality/bodyguard Christopher Boykin aka Big Black attends the Tony Hawk Foundation benefit at the Green Acres Estate on October 17, 2010 in Beverly Hills, California. (Photo by David Livingston/Getty Images)
(Back row 2nd from L) Johnny Knoxville, Mike Escamilla, Tony Hawk, Charles Annenberg Weingarten, Christopher Boykin, Rodney Mullen, (Front Row C) Mat Hoffman and Neal Hendrix arrive at the Tony Hawk: Shred Presents Stand Up For Skateparks Benefit on October 17, 2010 in Beverly Hills, California. (Photo by Joe Scarnici/WireImage)
LOS ANGELES, CA - FEBRUARY 08: Skateboarder Rob Dyrdek (L) and Christopher 'Big Black' Boykin arrive at the premiere of Paramount Pictures' 'Justin Bieber: Never Say Never' held at Nokia Theater L.A. Live on February 8, 2011 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
(L-R) Skateboarder Rob Dyrdek and Christopher 'Big Black' Boykin and guest arrive at the 'Justin Bieber: Never Say Never' Los Angeles Premiere held at Nokia Theatre L.A. Live on February 8, 2011 in Los Angeles, California. (Photo by Todd Williamson/WireImage)
HOLLYWOOD, CA - APRIL 14: Actor Christopher 'Big Black' Boykin attends the 'Mortal Kombat Legacy' digital series premiere celebration at Saint Felix II on April 14, 2011 in Hollywood, California. (Photo by Todd Oren/WireImage)
TV personality Christopher 'Big Black' Boykin performs inside of the Music Saves Lives 2011 Awareness Campaign kick off party at Next Door Lounge on May 11, 2011 in Hollywood, California. (Photo by Chelsea Lauren/WireImage)
HOLLYWOOD, CA - MAY 11: Reality TV Personality Christopher 'Big Black' Boykin arrives for the Music Saves Lives 2011 awareness campaign kick off party at Next Door Lounge on May 11, 2011 in Hollywood, California. (Photo by Paul Archuleta/FilmMagic)
Singer Nikola Rachelle Bedingfield (L) and TV personality Christopher 'Big Black' Boykin (R) inside of the Music Saves Lives 2011 Awareness Campaign kick off party at Next Door Lounge on May 11, 2011 in Hollywood, California. (Photo by Chelsea Lauren/WireImage)
DALLAS, TX - JUNE 18: (L-R) Christopher 'Big Black' Boykin and his wife Shannon in attendance at the Strikeforce event at American Airlines Center on June 18, 2011 in Dallas, Texas. (Photo by Esther Lin/Forza LLC/Forza LLC via Getty Images)
HOFFMAN ESTATES, IL - JULY 30: Television personality Christopher 'Big Black' Boykin attends the Strikeforce event at Sears Centre Arena on July 30, 2011 in Hoffman Estates, Illinois. (Photo by Josh Hedges/Forza LLC/Forza LLC via Getty Images)
LOS ANGELES, CA - OCTOBER 15: Christopher Boykin attends the 2nd Annual Rob Dyrdek Foundation Benefit at Fantasy Factory on October 15, 2011 in Los Angeles, California. (Photo by Jeff Kravitz/FilmMagic)
LOS ANGELES, CA - DECEMBER 08: TV Personality Christopher 'Big Black' Boykin attends the New Era LA Flagship Store Launch at New Era on December 8, 2011 in Los Angeles, California. (Photo by Charley Gallay/WireImage)
LOS ANGELES, CA - OCTOBER 15: Chelsea Chanel Dudley and Christopher Boykin attends the 2nd Annual Rob Dyrdek Foundation Benefit at Fantasy Factory on October 15, 2011 in Los Angeles, California. (Photo by Jeff Kravitz/FilmMagic)
LAS VEGAS, NV - JULY 7: (L-R) Christopher 'Big Black' Boykin & Rob Dyrdek during UFC 148 inside MGM Grand Garden Arena on July 7, 2012 in Las Vegas, Nevada. (Photo by Jeff Bottari/Zuffa LLC via Getty Images)
LOS ANGELES, CA - APRIL 13: Musician Christopher 'Big Black' Boykin attends the 2014 MTV Movie Awards at Nokia Theatre L.A. Live on April 13, 2014 in Los Angeles, California. (Photo by Steve Granitz/WireImage)
LAS VEGAS, NV - MAY 03: Television personality/recording artist Christopher 'Big Black' Boykin arrives at the pre-fight party for 'The Moment: Mayweather vs Maidana' at the MGM Grand Garden Arena on May 3, 2014 in Las Vegas, Nevada. (Photo by Gabe Ginsberg/FilmMagic)
LAS VEGAS, NV - SEPTEMBER 13: Television personality/recording artist Christopher 'Big Black' Boykin arrives at Showtime's VIP prefight party for 'Mahem: Mayweather vs. Maidana 2' at the MGM Grand Garden Arena on September 13, 2014 in Las Vegas, Nevada. (Photo by Gabe Ginsberg/FilmMagic)
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Dyrdek took to Twitter on Tuesday after news broke of Boykin's death to pay tribute to his friend in a series of heartfelt messages.

"My heart is broken. I don't want write this post. I don't want to believe that this is reality. I am so thankful for you," he tweeted alongside a photo of them from back in the day. "We truly were brothers that lived an unexpected unforgettable adventure. I just can't fathom that it would end so suddenly. [...] You will forever be in my heart."

"I am so thankful for this moment... thank you for being an amazing human being and brother," he tweeted with another photo of Boykin, playing with Dyrdek's child.

Christopher "Big Black" Boykin is survived by his 9-year-old daughter, Isis.

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