Williams, star of the new film "Old Dogs" arrives at the film's premiere in Hollywood in 2009.

In 1987, Robin Williams played disc jockey Adrian Cronauer in director Barry Levinsons comedy drama "Good Morning Vietnam."

This 1978 photo, originally released by ABC, shows Robin Williams on the set of ABC's sitcom "Mork and Mindy."

Williams with wife, Marsha, and son Zach enters the premiere of the 2002 movie "Death to Smoochy."

This 1982 photo, originally released by Warner Bros. Pictures, shows actor Robin Williams as T.S. Garp in the film "The World According to Garp."

Robin Williams, holding his Oscar high backstage at the 1998 Academy Awards after winning Best Supporting Actor for "Good Will Hunting."

Comedians Robin Williams, left, Whoopi Goldberg and Billy Crystal posing after hosting "Comic Relief" at Caesars Palace Hotel and Casino in Las Vegas in November 2006.

Robin Williams, posing in 2007 to promote his film "License To Wed," died in an apparent suicide. He was 63.

Robin Williams jokes with U.S. Postal rider Lance Armstrong before the start of the 15th stage of the Tour de France between Valreas to Villard-de-Lans, France, July 20, 2004.

Robin Williams performs at the NY Comedy Festival Event "Stand Up for Heroes: A Benefit for the Bob Woodruff Family Fund," in New York in November 2007.

Robin Williams speaks on stage at the "Idol Gives Back" fundraising special of "American Idol" in Los Angeles in 2008.

Hollywood director Ivan Reitman, center, poses with Robin Williams and Billy Crystal as they arrive for the premiere of their new film "Father's Day" in this 1997 file photo.

This 2009 photo shows actor Robin WIlliams from the film "World's Greatest Dad."

Robin Williams hugs the San Francisco Giants' mascot, Lou Seal, during Game 1 of the 2010 National League Division Series in San Francisco.

Robin Williams performs in New York at the 2012 Stand Up For Heroes benefit concert for injured service members and veterans.

Williams, wearing a camouflage jacket, entertains a cheering crowd of US Army troops at Baghdad airport in 2003.

Actor Robin Williams arrives at the 2006 New York Film Critics Circle Awards.