Hollywood star Colin Farrell has been dropped from the leading role in the new Bob Dylan film at the last minute.

The actor, who had been shortlisted with Richard Gere and Christian Bale for the part, will no longer play the legendary singer in the upcoming film I'm Not There.

The 29-year-old Irishman will be replaced by First Knight and Monsters Ball star Heath Ledger, apparently because director Todd Haynes changed his mind at the last minute.

US columnist Roger Friedman remarked, "The reason for Farrell's departure is unknown."

The film, which catalogues Dylan's life, is due to start shooting this summer.