Oscar-winning actor and comedian Robin Williams has been found dead in California from an apparent suicide.

In a news release, the Marin County Sheriff’s Office said Williams, 63, was found unconscious and not breathing inside his residence in Tiburon, Calif., Monday morning.

He was pronounced dead at the scene.

“At this time, the Sheriff’s Office Coroner Division suspects the death to be a suicide due to asphyxia, but a comprehensive investigation must be completed before a final determination is made.”

In a statement, Williams’ wife Susan Schneider said she is “utterly heartbroken” over the death of her husband and best friend. She said the world has lost “one of its most beloved artists and beautiful human beings.”

“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."

In another statement, Williams’ publicist said the actor had recently been battling severe depression.

“This is a tragic and sudden loss,” the publicist said. “The family respectfully asks for their privacy as they grieve during this very difficult time.”

Williams first made his mark as a comedian on stage and on TV, where he played an alien in the 1970s sitcom “Mork and Mindy.”

He later took on dramatic roles in movies like “Dead Poets Society” and “Good Will Hunting,” for which he won an Oscar in 1998.

More recently, Williams had returned to TV with “The Crazy Ones,” in which he played an ad agency owner.

He was open about previous problems with drugs and alcohol in the 1970s and ‘80s. He sought treatment in 2006 when he relapsed and returned to drinking after 20 years. Williams entered rehab in July for a brief stint in order to reconnect with the 12-step program.

Williams, who was born in Chicago in 1951, characterized himself in interviews as a shy kid who found his voice in high school when he joined the drama club.

As a stand-up comedian, Williams was known for his wildly energetic acts, and said he identified with other comedic giants like Richard Pryor and George Carlin. Loud and manic, Williams could ad-lib and do spot-on parodies of celebrities, including John Wayne and Keith Richards.

In a 1989 interview with The Associated Press, Williams described how comedy helped people deal with an at-times scary world.

"You look at the world and see how scary it can be sometimes and still try to deal with the fear," he said. "Comedy can deal with the fear and still not paralyze you or tell you that it's going away. You say, OK, you got certain choices here, you can laugh at them and then once you've laughed at them and you have expunged the demon, now you can deal with them. That's what I do when I do my act."

Some of his other film credits include “Awakenings,” “Deconstructing Harry” and “Hook.”

He won a Grammy in 2003 for Best Spoken Comedy Album with “Robin Williams – Live 2002.” He also won three Golden Globes, for “Mrs. Doubtfire,” “Good Morning, Vietnam” and “The Fisher King.”

Williams had several projects reportedly in the works, including another installment of “Night at the Museum.”

In a statement released Monday evening, U.S. President Barack Obama said Williams was one of a kind.

“He gave his immeasurable talent freely and generously to those who needed it most – from our troops stationed abroad to the marginalized on our own streets. The Obama family offers our condolences to Robin’s family, his friends, and everyone who found their voice and their verse thanks to Robin Williams.”

In his final post on Instagram in late July, Williams wished his daughter, Zelda Rae Williams, a happy birthday by posting an old photo of the pair:

And the Academy of Motion Picture Arts & Sciences posted this tribute on their Twitter:

With files from The Associated Press