Method-acting has a new torchbearer, in the emaciated form of an Irish actor who has redefined the notion of suffering for one's art.

Michael Fassbender, 31, starved himself for two months to play the IRA hunger-striker Bobby Sands in Hunger, which had its premiere at the Cannes Film Festival last night.

The film's makers believe his weight loss was essential for a convincing portrait of Sands's final weeks before he died, aged 27, in the Maze prison in Belfast in 1981. Fassbender's appearance was so frail that one doctor's receptionist said on seeing the actor: “That guy is really ill.”

Hunger is the directorial debut of the artist Steve McQueen, a former war artist in Iraq, and is one of the few British films singled out for this year's official programme.

McQueen, 38, told The Times yesterday: “This film is about a person who, in order to be heard, didn't eat. I knew from the beginning that we had to do it for real.

“It [hunger] really focused Michael on the role. He changed as a person, becoming clearer and more inward-looking. He's naturally lean and muscular, and he became skeletal. What was taken away was the muscle. You could see the skeleton on [Fassbender's] rib-cage and the hollows in the side of his head.”

Fassbender, who dropped from 73kg (166lb) to 57kg, survived on a diet of nuts, berries and sardines — about 500 calories a day. “I'd be lying if I said it wasn't tough,” he said.

Sands, who was jailed for weapons offences, was the IRA's most prominent martyr and the first of ten prisoners to die on hunger strike.

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