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, although some dare think otherwise.

If the shrieks of chanting moviegoers were enough to grant Heath Ledger an Academy Award, then by all means he 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 Oscarcast whereas Ledger will be dead for a year by the next awards ceremony.

Even though pouring reviews from the harshest critics near-unanimously praise and celebrate the late actor's performance, hinting at a possible posthumous Oscar nomination, who knows what the Oscar voters will really be looking for?

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. Almost unrecognizable beneath his makeup, Ledger's scar-faced character is world apart from Jack Nicholson’s well-respected take on the character.

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.

Deemed a harrowing screen villain, the schizophrenic mass-murderer Ledger plays in "The Dark Knight" represented the biggest challenge of his career.

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."