While preparing for the role of Joker, Heath Ledger locked himself in a motel room for about six weeks. During this isolation, he reached deep into the psychology of the character.
He made sure that he develops every Joker’s tic, voice, and sadistic-sounding laugh. For the voice, Heath tried to create a tone that didn’t create the same voice as jack Nicholson did in his 1989 performance as the joker.
Ledger’s explanation of the joker’s appearance was based on psychotic mannerisms and inspiration from some of the characters. We have seen joker constantly licking his lips in the movie, that was because of the prosthetic scars applied on Heath ledger. They used to fall off again and again, so Heath tried to lick them and keep them safe, later it became a part of the character.
Everyone must have seen the hospital demolition scene when the joker comes out from the hospital and tries to activate the detonator to make it explode, but it stops suddenly and joker turns around with weird gestures where his arms are moving and he’s acting confused, trying to make the detonator work again and so that it explodes again, scaring him and getting on the bus to escape. Trivia says it was all unplanned.
Many other actors were interested in playing the role of the joker, but Director Christopher Nolan wasn’t interested.
As Heath died in January 2008 at the age of 28 even before the film came out and after the release, Joker was beloved, and He created history as well by receiving praise and love from the audience.
Ledger’s death changed the sequel and to date, no one could be able to portray the role of Heath Ledger.
This is the only time two actors won Oscars for playing two different versions of the same character, Heath ledger (Best actor in a supporting role for the dark night and Joaquin Phoenix -best actor for joker).