Actor Peter O'Toole, who starred in Sir David Lean's 1962 film classic Lawrence of Arabia, died on Saturday aged 81, his agent has said.
He was being treated at London's Wellington hospital after a long illness, his agent added.
O'Toole's daughter Kate said the family was overwhelmed "by the outpouring of real love and affection being expressed towards him, and to us".
He received an honorary Oscar in 2003, having initially turned it down.
In a letter the actor asked the Academy of Motion Picture Arts and Sciences to delay it until he was 80, saying he was "still in the game and might win the bugger outright".
But when he finally clasped his statuette, he said: "Always a bridesmaid, never a bride, my foot."
O'Toole's agent said he was "one of a kind in the very best sense and a giant in his field".
Film critic Barry Norman described him as a "true movie star", who had "tremendous charisma".
Prime Minister David Cameron said: "My thoughts are with Peter O'Toole's family and friends. His performance in my favourite film, Lawrence of Arabia, was stunning."
Irish President Michael D Higgins added: "Ireland, and the world, has lost one of the giants of film and theatre.
"I was privileged to know him as a friend since 1969. I spent part of 1979 in Clifden where we met almost daily and all of us who knew him in the West will miss his warm humour and generous friendship."
Broadcaster Michael Parkinson told Sky News it was hard to be too sad about the news of his passing, and smiled as he said: "Peter didn't leave much of life unlived, did he?"
Actor, director and broadcaster Stephen Fry tweeted: "Oh what terrible news. Farewell Peter O'Toole. I had the honour of directing him in a scene. Monster, scholar, lover of life, genius …"
Writer and actor David Walliams recalled his memories of the actor, saying: "Matt & I had drinks with Peter O'Toole in LA a few years ago. He was hugely entertaining. The greatest company. A legend on screen and off."
Actress Sheridan Smith also tweeted her tribute, saying: "So sad about the death of the incredible Peter O'Toole :( He saw a play I did last year & sent me & all the cast presents after. A true gent!"
Actor Eddie Marsan hailed O'Toole's determination, tweeting: "'Waiting for the right part - you could wait forever. So I turn up and do the best I can.' That's an actor for you. R.I.P. Peter O Toole."
The Shield star Michael Chiklis added that O'Toole was the "original, hard drinking, classic, actor's actor", saying: "The piercing blue eyes of Lawrence of Arabia will never fade", while fellow US actor Neil Patrick Harris added: "Lucky to have worked with him for a month in Prague. Wonderful man, remarkable talent."
Journalist Piers Morgan also paid tribute, tweeting: "RIP Peter O'Toole. Spent one of the funniest days of my life with him at Lord's a few years ago. A brilliant actor & crazy, hilarious man."
O'Toole began his acting career as an exciting young talent on the British stage and his Hamlet in 1955 at the Bristol Old Vic, was critically acclaimed.
He hit international stardom when Sir David cast him as British adventurer T E Lawrence, the World War One soldier and scholar who led an Arab rebellion against the Turks.
Playwright Noel Coward once said that if O'Toole had been any prettier, they would have had to call the film "Florence of Arabia".
Lawrence of Arabia earned him the first of eight Oscar nominations, with his second coming for 1964's Becket, in which he played King Henry II to Richard Burton's Thomas Becket.
Burton and O'Toole's shared love of drinking garnered many headlines along with their performances.
O'Toole played Henry again in 1968 in The Lion in Winter, for which he received his third Oscar nod, opposite Katharine Hepburn.
His five other nominations were for Goodbye, Mr Chips in 1968, The Ruling Class in 1971, 1980's The Stunt Man, My Favorite Year  and finally for Venus in 2006.
Other performances included leading Shakespearean parts, comic roles in adaptations of PG Wodehouse and his famed starring role in 1989 in Keith Waterhouse's stage play Jeffrey Bernard Is Unwell.
It was a comedy about his old drinking pal Jeffrey Bernard, who wrote The Spectator magazine's weekly Low Life column.
O'Toole also had a reputation for riotous behaviour following bouts of drinking, but in the mid-70s he was diagnosed with pancreatitis and was warned by medics that more alcohol would prove fatal.
He had yards of his intestinal tubing - "most of my plumbing" - removed and he gave up drinking.
"If you can't do something willingly and joyfully, then don't do it,'' he once said. "If you give up drinking, don't go moaning about it; go back on the bottle. Do. As. Thou. Wilt."
'Waiting for the right part'
It was sometimes tough finding good roles, but he told the Independent on Sunday in 1990: "I take whatever good part comes along.
"And if there isn't a good part, then I do anything, just to pay the rent. Money is always a pressure. And waiting for the right part - you could wait forever. So I turn up and do the best I can."
In 1980 he starred in a critically panned production of Macbeth, but it was a sell-out after a drubbing from critics brought in audiences of curiosity seekers.
"The thought of it makes my nose bleed," he said years later.
Last July, after a career spanning 50 years and at the age of 79, O'Toole said he was retiring from the stage and screen.
However, last month it was announced he was being lined up for a role as a Roman orator in Katherine of Alexandria, a film scheduled for release next year.