Heath Ledger has signed to play the Joker in the sixth Batpic, with Christian Bale back as the Caped Crusader and Christopher Nolan returning to the director's chair.

Jonah Nolan -- the helmer's brother -- is penning the script based on a story by Christopher Nolan and David Goyer.

Batman Begins, the franchise's first installment in eight years, took in $205 million domestically and $166 million overseas.