Heath Ledger's role as the Joker in "The Dark Knight" is without a doubt his most significant performance of all, so impressive that it's been generating a lot of Oscar buzz.

Heath Ledger's co-stars in The Dark Knight have already expressed their opinion that the late actor win an Oscar for his portrayal of The Joker. Maggie Gyllenhaal, who plays the role of Rachel Dawes, said she would vote for Heath Ledger.

"In a way I feel funny thinking about the Oscars when he isn't alive, but at the same time I'm a member of the Academy and I would vote for him,” she said for People magazine.

Also Aaron Eckhart, who portrays Harvey Dent/Two Face said that he can vote for Heath Ledger and Sir Michael Caine, who plays butler Alfred Pennyworth, has the same opinion.

Heath Ledger would most likely become the second star to win the golden statue from the grave, following the late Peter Finch for 1976’s "Network."

When beloved Spencer Tracy passed away in 1967 after giving a dynamic, heartfelt performance in best picture nominee "Guess Who's Coming to Dinner," he was widely expected to win best actor, but lost to Rod Steiger ("In the Heat of the Night"). But things were different for Finch, who died from a heart attack just months before the Oscar cast whereas Ledger will be dead for a year by the next awards ceremony.

In "The Dark Knight," Ledger delivered his last complete film role before dying at the age of 28 from an accidental overdose of prescription drugs on Jan. 22 in Manhattan. His performance in the latest action-filled Batman flick has been shifted to centre stage, inflated by all the marketing fury of a big summer blockbuster, and even shaped into Heath's epitaph.

Drawing inspiration from sources as wide-ranging as Johnny Rotten and ventriloquists, Ledger's Clown Prince of Crime is anything but funny, instead, he's a sadistically gleeful force of nature who wants nothing more than to watch the world tear itself to pieces.

From facial tics to bad jokes, his devotion to the role took the Joker far from a garish comic book character to a nuanced madman that somehow does what every good villain can - makes you like him.

Unlike any other evil character, the Joker has no motive for his wrongdoing and in the same time, he is set to accomplish his ultimate goal: chaos. His painted face – white complexion, dark eyes and blood-crimson mouth – expresses nothing more than he is: ruthlessness.

The Joker is obviously not a premiere presence, the character has been present in previous movies focused on the adventures of Batman. But what Jack Nicholson or Cesar Romero realized is far from what Ledger played. Their characters were clowns, mere pranksters in comparison with the great cruelty of Ledger’s Joker.

Ledger, who never played a villain before, was cast by movie director Christopher Nolan as the Joker "because he's fearless." Nolan recently proclaimed that Ledger was the only person on his list of names after seeing the actor’s performance as the gay cowboy in "Brokeback Mountain."

Richard Corliss from Time has given a wonderful description of the part played by Heath Ledger.

“This villain, as conceived by Nolan and his scriptwriter brother Jonathan and incarnated with chilling authority by Ledger, is not the elegant sadist of so many action films, nor the strutting showman played by Jack Nicholson in Tim Burton's 1989 Batman. He isn't a father figure or a macho man. And though he invents several stories about how he got his (facial and psychic) scars, he's not presented as the sum of injustices done to him. This Joker is simply one of the most twisted and mesmerizing creeps in movie history”, Curliss wrote.

Roger Ebert also greeted the remarkable performance of Ledeger. “The key performance in the movie is by the late Heath Ledger, as the Joker. Will he become the first posthumous Oscar winner since Peter Finch?”, Ebert said in his review of “The Dark Knight”