WHO PLAYED THE JOKER BETTER?

Heath Ledger thought landing the demanding role of the Joker was a dream come true - but now some think it was a nightmare that led to his tragic death.

Jack Nicholson, who played the Joker in 1989 - and who was furious he wasn't consulted about the creepy role - offered a cryptic comment when told Ledger was dead.

"Well," Nicholson told reporters in London early Wednesday, "I warned him."

Though the remark was ambiguous, there's no question the role in the movie earmarked as this summer's blockbuster took a frightening toll.

Ledger recently told reporters he "slept an average of two hours a night" while playing "a psychopathic, mass-murdering, schizophrenic clown with zero empathy ...

"I couldn't stop thinking. My body was exhausted, and my mind was still going."

Prescription drugs didn't help, he said.

Ledger's ghastly image as the Clown Prince of Crime in "Dark Knight" has been an Internet sensation since trailers were released in December, featuring Ledger in full death's-head mode.

His face chalk-white, his hair green and his mouth a sliced red grimace, the handsome 28-year-old Australian actor looked frighteningly true to the character in the Alan Moore graphic novel, "Batman: The Killing Joke."

The movie wrapped filming in the fall - right after Ledger's breakup with actress Michelle Williams - and post-production work finished not long after.

While "Dark Knight" is the film that will stand as Ledger's cinematic gravestone, insiders say the flick, set for a July 18 release with Christian Bale as Batman, won't suffer from his death.

"Ledger's portrayal of the Joker is already one of the most anticipated screen characters of the whole year," says Gitesh Pandya, editor of the movie tracking site boxofficeguru.com