Actor Robin Williams has been found dead in his home in a suspected suicide, according to reports.

Officials are investigating the death of the 63-year-old who was found unconscious inside his home in northern California.

The Marin County Sheriff's Office said investigations into the circumstances of the death are currently underway by the Investigations and Coroner Divisions of the Sheriff's Office, officials said.

Investigators said that Williams was last seen alive at his residence, where he resides with his wife, at 10pm on Sunday.

Williams' publicist Mara Buxbaum told the Hollywood reporter, "Robin Williams passed away this morning. He has been battling severe depression of late. This is a tragic and sudden loss. The family respectfully asks for their privacy as they grieve during this very difficult time."

His wife, Susan Schneider, 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."

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.

A forensic examination is currently scheduled for August 12, 2014 with subsequent toxicology testing to be conducted.

Williams, a four-time Oscar nominee, won a supporting actor Oscar for Good Will Hunting. He most recently starred in CBS' comedy The Crazy Ones, which lasted only one season.

He recently checked into a renewal centre in an effort to maintain his sobriety, according to the Hollywood reporter.

Williams has been a prominent fixture on screens since the 1970's where he has portrayed a wide variety of characters.

He earned Oscar nominations for Best Actor for his varied roles in Good Morning, Vietnam, The Fisher King and Dead Poets Society.

He showed his versatility in a wide range of films, including: The World According to Garp (1982), Moscow on the Hudson (1984), Hook (1991), Patch Adams (1998) Flubber (1997), Toys (1992) and Jumanji (1995).

He won four Grammy Awards. He also won Emmy Awards for his TV specials Carol, Carl, Whoopi and Robin andABC Presents a Royal Gala.