Robin Williams in Dead Poets Society |
Police in Marin County, California, reported that the Dead Poets Society star had been found unconscious and unresponsive at his residence in Tiburon.
Sheriff's Lt Keith Boyd said Williams had been treated for depression and killed himself by hanging.
The star - who won a best supporting Oscar for Good Will Hunting - was also Academy Award nominated for The Fisher King, Dead Poets Society and Good Morning, Vietnam.
Susan Schneider, who has been married to Williams since 2011, issued a statement. She said: "This morning, I lost my husband and my best friend, while the world lost one of its most beloved artists and beautiful human beings. I am utterly heartbroken.
"On behalf of Robin's family, we are asking for privacy during our time of profound grief. As he is remembered, it is our hope the focus will not be on Robin's death, but on the countless moments of joy and laughter he gave to millions."
As the news broke on social media sites, stars tweeted their tributes.
Steve Martin - who starred with him in a stage version of Waiting For Godot - tweeted: "I could not be more stunned by the loss of Robin Williams, mensch, great talent, acting partner, genuine soul."
And fellow comedian Ellen DeGeneres tweeted: "I can’t believe the news about Robin Williams. He gave so much to so many people. I’m heartbroken."