
The New York premiere has been dedicated to the late actor, and the end of the movie includes a memoriam to him.
In Britain's Empire Magazine director Christopher Nolan called Ledger's portrayal of the villain "the absolute extreme of anarchy and chaos."
"We didn't want to show what made him do the things he's doing, because then he becomes less threatening. I like to say he cuts through the movie like [the shark in] 'Jaws,'" Nolan said. "He just kind of comes and goes and causes complete mayhem."
The Dark Night will be released in theaters July 18. In it, Christian Bale reprises his role as Batman, and Aaron Eckhart plays district attorney Harvey Dent.