Robin Williams is seen wearing a letter jacker during his senior year at Redwood High School in Larkspur, Calif., 1969.

Robin Williams and his former wife Valerie Williams after "Saturday Night Live" Taping in New York City, Nov. 11, 1978.

This Nov. 12, 1979 file photo shows actor-comedian Robin Williams, third from right, dressed as a cheerleader with the Broncos' Pony Express cheerleaders during the filming of an episode of "Mork & Mindy," in Denver.

Robin Williams during People For the American Way gala birthday dinner at Beaux Arts Puck Building in New York City, New York on Oct. 24, 1985.

Robin Williams is seen at the Academy Awards, Hollywood, Calif., March 25, 1996.

Robin Williams during Robin Williams Footprint Ceremony at Mann's Chinese Theatre in Hollywood, Calif., Dec. 22, 1998.

Robin Williams performs; "On Stage at the Kennedy Center: The Mark Twain Prize" on Oct. 15, 2001.

Actor-comedian Robin Williams entertains the troops during the United Service Organizations (USO) tour at Baghdad International Airport Dec. 16, 2003.

Robin Williams at the HBO & AEG Live's "The Comedy Festival" Show at Caesars Palace in Las Vegas, Nevada, 2006.

Robin Williams and his family are seen at the Man of the Year premiere in Los Angeles, Oct. 4, 2008.

This Nov. 9, 2009 file photo shows actor Robin Williams, right, and his wife Susan Schneider at the premiere of "Old Dogs" in Los Angeles.

Robin Williams appears onstage at The 2012 Comedy Awards in New York, Saturday, April 28, 2012.

Robin Williams at SiriusXM's 'Town Hall' series at SiriusXM Studios on Sept. 25, 2013 in New York City.

Actor Robin Williams enters the "Late Show With David Letterman" taping at the Ed Sullivan Theater in this Sept. 25, 2013, file photo in New York City.