20 Behind-the-Scenes Secrets from The Dark Knight
Heath Ledger Locked Himself in a Room For Over a Month
Heath Ledger’s performance as the Joker is widely regarded as one of the best in the history of comic book movies. When you consider the lengths the actor went to for the role, that shouldn’t come as a huge surprise. Because he came onto The Dark Knight pretty early in the filming process, he was able to spend more than a month preparing.
During that time, Heath locked himself in a hotel room, studying source material and practicing different voices. He also spent a lot of his time journaling. When he left the room, he had the character ready to go.