Robin Williams, the US actor and comedian who has been found dead in an apparent suicide at the age of 63, won legions of fans with his frenetic energy, quick-fire improvisations and ability to mimic other famous people.
Those skills enabled him to create such delightful comic characters as Mrs Doubtfire, the faux Scottish nanny he disguised himself as in the 1993 hit, and the shape-shifting genie in Disney's Aladdin - a free-wheeling force no bottle could contain.
Yet Williams was also capable of more nuanced work, receiving a best supporting actor Oscar for playing a sympathetic yet troubled psychologist who comes to Matt Damon's aid in 1997's Good Will Hunting.
He could also play against his ebullient persona and the affection audiences had for him by bringing chilling psychotic villains to life in films such as Insomnia and One Hour Photo.
Born on 21 July 1951 in Chicago, Illinois, the young Williams developed a quick wit as a means of overcoming shyness and boosted his confidence further by joining his school's drama club.
After leaving he was accepted into New York's famed Juilliard School, where he was a contemporary of Superman actor Christopher Reeve and Frasier star Kelsey Grammer in the mid-1970s.
There he was taught by the distinguished actor John Houseman, who suggested he should consider stand-up comedy as a potential career path.
Appearances on the comedy circuit and The Richard Pryor Show followed, though it was his cameo appearance on Happy Days as an alien called Mork that gave him his breakthrough.
The character, an eccentric extra-terrestrial who travels from the planet Ork to study earth and its inhabitants, inspired a spin-off, Mork and Mindy, that made Williams a star.
The show, which ran from 1978 to 1982, spawned a memorable catchphrase in "Nanu Nanu", Mork's friendly greeting, as well as providing a platform for Williams's manic talent for improvisation.
The actor was subsequently cast as Popeye in a live-action vehicle for the enduring cartoon character that proved to be a costly failure when released in December 1980.
"If you watch it backwards, it has a plot," he would later say of Robert Altman's film, describing the shoot as "a pretty crazy experience".
Williams made a stronger impression in The World According to Garp, an adaptation of the John Irving novel about a young man with an unusual upbringing trying to find his place in the world.
It was not until 1987's Good Morning Vietnam, though, that Hollywood found a suitable vehicle for his particular skills set and off-the-cuff ad-libbing.
His portrayal of Adrian Cronauer, an irreverent DJ broadcasting to US forces during the Vietnam conflict, earned him his first Oscar nomination for best actor.
His second came two years later for Dead Poets Society, in which he played an inspirational English teacher at a strict New England boys' school who encourages his pupils to think for themselves.
Another nomination followed for his performance as a homeless man in Terry Gilliam's film The Fisher King, though it was not until 1998 he was finally recognised by the Academy for his Good Will Hunting role.
"This might be the one time I'm speechless," he said as he collected his Oscar, adding that his father had advised him to have "a back-up profession, like welding" when he was first told his son wanted to be an actor.
The mid-1990s saw him take on some of his best-loved roles: the grown-up Peter Pan in Steven Spielberg's Hook, the cross-dressing father who becomes Mrs Doubtfire, and Jumanji's Alan Parrish, a man who has grown up inside the world of a children's board game.
He was also heard as the voice of the Genie in Aladdin, an anarchic entity who grants the hero three wishes when not impersonating Arnold Schwarzenegger, Groucho Marx, Robert De Niro and Ethel Merman.
Williams would go on to claim he had not been adequately paid for his work by the Walt Disney studio, joking "the only reason Mickey Mouse has three fingers is because he can't pick up a cheque".
Subsequent vehicles like Patch Adams and Bicentennial Man were less well-received, prompting him to explore darker roles like the serial killer who torments Al Pacino's detective in the Alaska-set Insomnia.
"People think of me as likeable, so the appeal was to play against those expectations and explore those areas that normally you'd have to do prison time for," he told Empire magazine in 2010.
He also found himself playing presidents, both real (Theodore Roosevelt in Night at the Museum and its sequel, and Dwight D Eisenhower in The Butler) and fictional (Tom Dobbs, the comedian elected president in 2006's Man of the Year).
Some may find it fitting, then, that his death was marked by the current holder of that office, who said he had been "one of a kind" and had "ended up touching every element of the human spirit".
Williams recently appeared as an eccentric advertising executive in US sitcom The Crazy Ones. The show, in which Sarah Michelle Gellar played his daughter, was cancelled in May after one season.
Later this year he will be seen alongside Ben Stiller in the third Night at the Museum film, once again playing a waxwork dummy of Roosevelt who magically comes to life.
Williams struggled with drink and drug addictions in the 1970s and 1980s, later joking that cocaine was "God's way of telling you you are making too much money".
After 20 years of sobriety, he fell off the wagon in the 2000s and sought treatment for alcoholism. "I went to rehab in wine country just to keep my options open," he joked.
He was diagnosed with heart problems and had surgery in 2009 to replace a heart valve, remarking afterwards the procedure had given him "some great new material".
Williams was married three times and had three children. He is survived by his widow Susan Schneider, his daughter Zelda and his sons Zachary and Cody.