Ledger was first choice for Joker role

The Dark Knight director Christopher Nolan has revealed that Heath Ledger was always his first choice for the role of The Joker in the Batman sequel.

Nolan denied rumours that Robin Williams and Sean Penn were on the shortlist for the part when casting for the movie was taking place.

"Heath was the only one on it. I knew he was it from the start," Christopher told Entertainment Weekly. "The guy had serious nuts. What I needed was someone who wouldn't be afraid of the comparison with Jack Nicholson. And then I saw Heath's incredible performance in Brokeback Mountain. Such a lack of vanity."

He continued: "This was an actor who wasn't afraid to bury himself in his character - to a massive extent."

Nolan added that the late actor worked hard on his preparation for the role, perfecting The Joker's cackle with a voice coach and even applying his own make-up.

"He tried to articulate to me what he was doing with his voice, but it was sometimes hard to understand," Christopher explained. "He said he wanted the voice to have a mocking quality, a sort of disconnectedness. He started applying the make-up himself."

Ledger died in January following an accidental overdose of prescription drugs.