Heath Ledger's performance as the Joker in “The Dark Knight” is one of the all-time greats. He owns every frame he's in and dominates the picture to the point where Batman almost becomes a supporting character in his own movie.
Ledger's death following production added an unnecessary mystique to the performance, providing a bizarre mythology that Ledger got in too deep and that it cost him his life. While that may play into the notion of great art require sacrifice, it disregards the actual work acting requires as well as the personal demons Ledger probably wrestled with.
In Joseph McCabe's new book “100 Things Batman Fans Should Know & Do Before They Die”, Christian Bale recalls how Ledger wanted to be physically beaten during the interrogation scene because he didn't want to break character, according to a report on Collider. It quotes:
“Our first scene was in an interrogation room together, and I saw that he's a helluva actor who's completely committed to it and totally gets the tone that Chris [Nolan] is trying to create with this. We're not going for actors revealing their enjoyment of playing a wacky caricature. We're treating this as serious drama. You go into character and you stay in the character. I love that. I find that so ridiculous that I love it, and I take that very seriously. Heath was definitely embracing that. When he was in the makeup and the garb he was in character the whole time; and when he took it off he was absolutely fantastic company to be around.
“As can be seen in the movie, Batman starts beating the Joker and realizes that this is not the ordinary foe. Because the more I beat him the more he enjoys it. The more I'm giving him satisfaction. Heath was behaving in a very similar fashion. He was kinda egging me on. I was saying, 'You know what, I really don't need to actually hit you. It's going to look just as good if I don't.' And he's going, 'Go on. Go on. Go on…' He was slamming himself around, and there were tiled walls inside of that set which were cracked and dented from him hurling himself into them. His commitment was total.
The anecdote, coming from Bale who himself is known for his incredible commitment to his roles, definitely adds a layer to the person Ledger became while filming “Dak Knight”, and is sure to have fans of his work busy in discussion over the character and the film.