George Clooney has endorsed presidential candidate Hillary Clinton with a letter sent to supporters of the former secretary of state.
In the letter, which was sent in an email from the Clinton campaign, Clooney calls her "the only grown-up in the room" during the 2016 election.
He called Trump a "xenophobic fascist" in an interview with the Guardian earlier in March and referenced Trump's rhetoric in the letter.
"If you listen to the loudest voices out there today, you'd think we're a country that hates Mexicans, hates Muslims, and thinks that committing war crimes is the best way to make America great again," he wrote. "The truth is that the only thing that would prevent America from being great would be to empower these voices."
He wrote that Hillary has been the "one consistent voice" in "all of this clutter."
See Clooney through the years:
George Clooney through the years
George Clooney endorses Hillary Clinton and says she's 'the only grown-up in the room'
UNITED STATES - MAY 02: ROSEANNE - 'Let's Call It Quits' - Season One - 5/2/89, Roseanne has difficulty accepting new rules from a tough new supervisor at the factory. George Clooney (Booker) stars., (Photo by ABC Photo Archives/ABC via Getty Images)
THE FACTS OF LIFE -- Pictured: George Clooney as George Burnett -- Photo by: Ron Tom/NBCU Photo Bank
ER -- SEASON 4 -- Pictured: George Clooney as Doctor Doug Ross (Photo by Sven Arnstein/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 1404 -- Pictured: (l-r) Actor George Clooney during an interview with host Jay Leno on June 25, 1998 -- (Photo by: Margaret Norton/NBC/NBCU Photo Bank via Getty Images)
NBC SUNDAY NIGHT AT THE MOVIES- COMBAT HIGH -- Pictured: (l-r) Keith Gordon as Max Mendelsson, George Clooney as Maj. Biff Woods -- (Photo by: Paul Drinkwater/NBC/NBCU Photo Bank via Getty Images)
George Clooney and Julia Roberts during 11th Annual Critics' Choice Awards - Backstage and Audience at Santa Monica Civic Auditorium in Santa Monica, California, United States. (Photo by Chris Polk/FilmMagic)
George Clooney and Michelle Pfeiffer on phones in backseat of car in a scene from the film 'One Fine Day', 1996. (Photo by 20th Century-Fox/Getty Images)
George Clooney, Mark Wahlberg And Ice Cube Star In 'Three Kings.' '99 Wb And Village Roadshow Film Limited (Photo By Getty Images)
1999 George Clooney stars in the latest season of 'ER.'
NEW YORK, NY - MARCH 02: Actor George Clooney attends SeriousFun Children's Network's New York City Gala at Avery Fisher Hall, Lincoln Center on March 2, 2015 in New York City. (Photo by Dimitrios Kambouris/Getty Images)
WESTWOOD, CA - DECEMBER 5: Actor George Clooney attends the 'Ocean's Eleven' Westwood Premiere on December 5, 2001 at the Mann Village Theatre in Westwood, California. (Photo by Ron Galella, Ltd./WireImage)
George Clooney (Photo by Vera Anderson/WireImage)
US actor/movie maker George Clooney speaks during the global launch of 100 LIVES initiative and the announcement of a new humanitarian prize in New York on March 10, 2015. The 100 LIVES, initiated to express gratitude to individuals and institutions whose heroic actions saved Armenian lives during the Genocide 100 years ago, is to address the issues of genocide, human rights violations and the power of positive action. AFP PHOTO/JEWEL SAMAD (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
HOLLYWOOD - MARCH 31: Actor/director George Clooney arrives to the premiere of Universal Pictures' 'Leatherheads' held at Grauman's Chinese Theatre on March 31, 2008 in Hollywood, California. (Photo by Kevin Winter/Getty Images)
BERLIN, GERMANY - FEBRUARY 8: (L to R) Actors Natascha McElhone, Ulrich Tukur, George Clooney and director Steven Soderbergh attend the 53rd Berlinale Film Festival February 8, 2003 in Berlin, Germany. Their new film 'Solaris' was written and directed by Soderbergh. (Photo by Kurt Vinion/Getty Images)
David Strathairn and George Clooney during 2005 Venice Film Festival - George Clooney - Sighting in Venice Lido, Italy. (Photo by George Pimentel/WireImage)
US actor and director George Clooney (R) and co-star Renee Zellweger arrive in London's Leicester Square on April 8, 2008 to attend the European Premiere of the film, Leatherheads directed by Clooney. AFP PHOTO / Max Nash (Photo credit should read MAX NASH/AFP/Getty Images)
LOS ANGELES - NOVEMBER 14: Actor George Clooney speaks to the media at the Four Seasons Hotel on November 14, 2006 in Los Angeles, California. (Photo by Piyal Hosain/Fotos International/Getty Images)
Nominee for Best Actor ('Michael Clayton') George Clooney (R) and gilrfriend Sarah Larson arrive for the 80th Annual Academy Awards at the Kodak Theater in Hollywood, California on February 24, 2008. AFP PHOTO / STAN HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)
Actor George Clooney speaks during the 80th Annual Academy Awards held at the Kodak Theatre on February 24, 2008 in Hollywood, California. (Photo by Kevin Winter/Getty Images)
Matt Damon and George Clooney (Photo by Lester Cohen Archive/WireImage)
George Clooney at junket for 'Good Night and Good Luck,' a new movie. (Photo by Michael Albans/NY Daily News Archive via Getty Images)
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"As this primary process continues, Hillary could soon have an insurmountable delegate lead and with that, the Democratic nomination," he added. "That would then make her the only grown-up in the room. And if ever there was a time for a grown-up, that time is now."
Clooney and his wife, Amal, are hosting back-to-back fundraisers for Clinton in April. All proceeds will go to the Hillary Victory Fund.
The letter invited Clinton supporters to enter a contest to meet him, Amal, and Clinton at the Clooneys' home on April 16. Supporters can enter by donating or signing up.