UPDATE (5:02 PM PST): Williams' wife and publicist have spoken out on the comedian's death (via The Hollywood Reporter):

Wife Susan Schneider: "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."

Publicist Mara Buxbaum: "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."

[Hollywood and the world reacts to Robin Williams passing.]

ORIGINAL STORY:

Oscar-nominated actor Robin Williams has been found dead at his home at the age of 63, authorities reported on Monday. The following is a statement from the Marin County Sheriff's Office Coroner Division:

On August 11, 2014, at approximately 11:55 am, Marin County Communications received a 9-1-1 telephone call reporting a male adult had been located unconscious and not breathing inside his residence in unincorporated Tiburon, CA. The Sheriff's Office, as well as the Tiburon Fire Department and Southern Marin Fire Protection District were dispatched to the incident with emergency personnel arriving on scene at 12:00 pm. The male subject, pronounced deceased at 12:02 pm has been identified as Robin McLaurin Williams, a 63 year old resident of unincorporated Tiburon, CA.

An investigation into the cause, manner, and circumstances of the death is currently underway by the Investigations and Coroner Divisions of the Sheriff's Office. Preliminary information developed during the investigation indicates Mr. Williams was last seen alive at his residence, where he resides with his wife, at approximately 10:00 pm on August 10, 2014. Mr. Williams was located this morning shortly before the 9-1-1 call was placed to Marin County Communications. 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. A forensic examination is currently scheduled for August 12, 2014 with subsequent toxicology testing to be conducted.

Born July 21, 1951 in Chicago, Illinois, Williams attended the Juilliard School before breaking out as the wisecracking alien Mork on "Happy Days" and its hit spinoff "Mork & Mindy" opposite Pam Dawber. During this time he also became one of the country's premiere standup comedians, with a trio of HBO comedy specials leading into a co-hosting gig at the 1986 Academy Awards.

On the big screen, Williams made his acting debut in the little-seen 1977 comedy "Can I Do It 'Till I Need Glasses," though he wouldn't make a splash until three years later with his title role in Robert Altman's live-action "Popeye." Other major roles during this period included "The World According to Garp" (1982), "Moscow on the Hudson" (1984) and Barry Levinson's 1987 war comedy "Good Morning, Vietnam," for which he was nominated for an Academy Award. He followed that up with an Oscar nod for the 1989 drama "Dead Poets Society" and, two years later, yet a third nomination for his role in Terry Gilliam's "The Fisher King" opposite Jeff Bridges.

Throughout the next decade Williams' silver-screen star continued to rise with a stunning string of major box-office successes including Steven Spielberg's "Hook," Disney's animated "Aladdin" (in which he so memorably voiced the wisecracking Genie), gender-bending comedy "Mrs. Doubtfire," "Jumanji," "The Birdcage," "Patch Adams" and Gus Van Sant's "Good Will Hunting," for which he would finally take home an Academy Award for Best Supporting Actor.

Beginning in the late '90s Williams' box-office fortunes began to decline somewhat with flops like "What Dreams May Come," "Bicentennial Man" and the critically-lambasted "Death to Smoochy," though his filmography was still peppered with acclaimed performances including the 2002 thriller "One Hour Photo," in which he played a mentally unstable photo technician who forms an unhealthy obsession with a young family.

For all of his career successes, Williams was dogged by substance abuse for much of his adult life, with a well-documented cocaine problem in the '70s and '80s and a stay in rehab in 2006 to kick an addiction to alcohol. Just last month he checked into the Hazelden Addiction Treatment Center near Lindstrom, Minnesota in an attempt to maintain his sobriety.

Williams most recently starred on the now-cancelled CBS television sitcom "The Crazy Ones" opposite Sarah Michelle Gellar; upcoming film releases include the family-adventure threequel "Night at the Museum: Secret of the Tomb" and "A Friggin' Christmas Miracle" opposite Lauren Graham and Joel McHale.

In addition to his Oscar win, Williams was the recipient of five Grammys, two Emmys, four Golden Globes and two Screen Actors Guild Awards during his lifetime. His charitable work included co-founding the philanthropic Windfall Foundation with ex-wife Marsha Garces, co-hosting a series of "Comic Relief" specials to benefit the homeless alongside fellow comedians Whoopi Goldberg and Billy Crystal, and performing for American troops in Iraq and Afghanistan on a number of USO tours.

Williams is survived by wife Susan Schneider (m. 2011) and children Zachary, Zelda and Cody.

Sound off with your appreciations for the late star in the comments.