Nolan: 'Ledger Made The Dark Knight A Success'

Ledger plays The Joker in the movie, the last full film role he completed before his death in January (08) from an accidental drug overdose. And Nolan insists Ledger made the movie a hit.

Speaking at The Dark Knight's Japanese premiere on Monday (28Jul08), the British filmmaker said, "(He was) what The Joker in our film would need to be.

"(We were) looking for an actor with the fierceness, excitement and teeth to do our version of the Joker."

Christian Bale, who plays Batman in the record-breaking film, also found time to praise Ledger, telling a press conference, "It's satisfying to see people celebrating the incredible talent of Heath. I just want him to be recognised."

In just 10 days since the film's release in America, The Dark Knight has taken an astonishing $440 million (GBP150 million) at movie theatres worldwide, breaking almost every box office record in the U.S.