hey, just to inform you the shooting for The Dark Knight was wrapped up by November 2007. Late Heath Ledger passed away in Janunary 2008 in his apartment. Moreover the co-actors have told that he was quite a normal person between takes. So it is definitely not over-doing 'JOKER' that took toll on him, it was an accidental prescription drug overdose. The fact that a GEM of an actor is lost, makes THE DARK KNIGHT all the more hyped.
