Sean Penn has agreed to star in a drama based on the life of gay US politician Harvey Milk.

The Mystic River actor will play the lead role in the Gus Vant Sant-directed film, which according to the Hollywood Reporter may also feature Matt Damon.

Milk was San Francisco's first openly gay supervisor, who was shot dead in 1978. His political opponent Dan White was sentenced to seven years in jail for the murder, but he committed suicide later that year.

The biopic is due to start shooting in San Francisco in December, following the agreement of a distribution deal.