Sean Penn has been signed to play gay rights icon Harvey Milk in one of two dueling biopics about the first openly gay man to be elected to public office in the USA. Penn will take on the title role in Gus Van Sant's Milk.

We reported earlier when rumors came out of the Toronto Film Festival saying that Penn was in talks to play Milk. At the time Matt Damon was also discussing the possibility of playing Milk's killer, Dan White (who also killed Mayor George Moscone). Damon is reported as having dropped out due to scheduling conflicts.

The other Milk biopic in development is Bryan Singer's adaptation of The Mayor Of Castro Street, the book written by out journalist Randy Shilts. According to Variety, is reporting that project is currently in limbo due to the writers' strike: a final script wasn't turned in before the strike began and, therefore, the project won't be able to move forward until the strike ends.

Andy Towle adds a couple additional casting rumors about the film, saying that James Franco could be playing Milk's brother, Robert, while Mark Wahlberg might take on the role of Dan White. Towle warns that these are completely unsubstantiated, so take them with a grain of salt.