Academy Award-winning performer Sir Anthony Hopkins said he was never "cut out to be an actor".
His Hannibal Lecter is one of the all-time great movie villains, but the star of The Dresser said his venerated career was a "mistake".
Speaking to the Associated Press, he said: "I wasn't cut out to be an actor.
"I wanted to be a musician, but I drifted into this business by mistake.
"I'm still looking over my shoulder thinking somebody will say, 'Sorry, Tony, you're in the wrong business.'"
The business has no such doubts. Sir Anthony gained Oscar nominations for playing the eponymous president in Nixon, John Quincy Adams in slavery drama Amistad and the loyal butler Stevens in The Remains Of The Day.
He won a best-actor Oscar in 1991 for cannibalistic serial killer Hannibal in The Silence Of The Lambs.
In The Dresser, the 78-year-old Welsh actor plays Sir, a cranky, creaky old thespian mounting a threadbare wartime production of King Lear and battling the infirmities of age.
Sir Ian McKellen co-stars as Norman, his devoted dresser, in a mesmerisng display of talent from two of Britain's acting greats.
Speaking of his own experience as part of Laurence Olivier's company at the National Theatre, Sir Anthony said it was "absolute purgatory".
"All those endless tours as a walk-on, running on in wrinkled tights to Olivier's Othello.
"I'm not a good team player. I'm a bit wild and a bit crazy. I just want to break out and do something else, and I just couldn't take the routine of it. Wet Wednesday afternoons in the Waterloo Road - I just thought, God, what a depressing life."
He infamously walked out of a 1973 stage production of Macbeth in mid-run, and has not performed for the theatre in almost 30 years, with one of his last stage roles being King Lear at the National in 1986.
He said it was not a great success - he was "too young, too confused and too unsettled" to play Shakespeare's fallen king.
"I just wanted to get the hell out of the theatre. It was nobody's fault - David Hare did a fine production, but I just wasn't up to it."
Producer Colin Callender said the TV movie started as an attempt to lure Sir Anthony back on to the stage in a revival of The Dresser, but he said he would only do it for television.
It has emboldened him to tackle King Lear again and he will play the king in a television version made by Colin's company for the BBC.
And it has made him rethink his aversion to the stage.
"Ian's trying to get me to go back to the stage, but I don't think I've got the courage to do it," he said.
"I don't think so. I'm not sure. It's something I just let waft around in my head. Maybe one day."