Sir Michael Caine has revealed the secret to his long career is taking roles that seem almost impossible to him.

The Italian Job star learned how to conduct an orchestra for his latest movie Youth, in which he plays a retired maestro on holiday in the Alps with no plans to resume his career until he receives a request from the Queen.

Speaking on the red carpet at the Los Angeles premiere at the Directors Guild of America, Sir Michael, 82, said keeping things fresh has been the key to his success.

Michael Caine and wife Shakira at the LA premiere of Youth
Sir Michael and wife Shakira at the LA premiere of Youth (Richard Shotwell/Invision)

“I never did the same thing over and over again, I keep testing myself. I didn’t become an actor to become rich and famous, that’s not possible.

“If you’re a young actor, a 22-year-old Cockney guy, you’re not going to become a movie star and be rich, I only became an actor to be the best possible actor I could be and that stays with me all my life and it’s still the same.

Sir Michael and Harvey Keitel in the film
Sir Michael and Harvey Keitel in the film (Gianni Fiorito/20th Century Fox)

“So each time I do a movie I do something that is almost impossible, like for me to play a classical conductor or composer. I’m not from that background but it seemed to work out all right.”

Asked what keeps him going, the British star said: “In the movies you don’t retire, movies retire you. I’ve mentally retired but I keep getting these scripts I can’t refuse so I went back to work.

“But now I don’t have a job, I don’t have a script, and it would take something incredible to get me out of bed in the morning.”

Sir Michael Caine, Jane Fonda and Harvey Keitel on the red carpet
Sir Michael, Jane Fonda and Harvey Keitel on the red carpet (Lionel Cironneau/AP)

Jane Fonda, 77, plays an ageing actress in the film but said she feels younger now than she did 50 years ago.

“When I was in my 20s and 30s I was really old, I’m so young now, in my soul. I’ve managed to fight cynicism and stay open and curious and feel kind of like a novice – it’s an attitude.”

Youth will be released in UK cinemas on January 29, 2016.