Sacha Baron Cohen is set to appear in Steven Spielberg's movie.

The 'Borat...' star - who recently revealed he was killing off his alter egos Borat and Ali G - will play '60s Jewish activist Abbie Hoffman in a film about the Chicago Seven after Spielberg talked him into taking the role.

Hoffman was arrested and tried for conspiracy and inciting to riot as a result of his role in anti-Vietnam war protests during the 1968 Democratic National Convention in Chicago.

He was among the group that came to be known as the Chicago Seven (originally the Chicago Eight), which included Jerry Rubin, Black Panther Party co-founder Bobby Seale, David Dellinger, Rennie Davis, John Froines, Lee Weiner and future California state senator Tom Hayden.

Bobby Seale's trial was severed from the others, who then became the Chicago Seven.

Cohen has also signed a deal for a movie to be made about his gay Austrian TV host Bruno.

He is set to receive $15 million and a 15 per cent cut of box-office receipts.