Can 'Dark Knight' leap into Oscars history?

The superhero blockbuster could be a best picture contender, along with 'Slumdog Millionaire,' 'Benjamin Button' and 'Frost/Nixon.'

It's no joke.

The decade's biggest blockbuster, " The Dark Knight," could become the first superhero movie to be nominated for an Oscar for best film when the Academy of Motion Picture Arts and Sciences announces the nominations for the 81st Annual Academy Awards early Thursday morning.

The critically acclaimed Batman adventure has been developing a lot of momentum lately especially with its nominations for the Producers Guild of America top prize, the Directors Guild of America Award, the Writers Guild of America Award and several crafts honors.

At least one "Knight" nomination is all but certain -- best supporting actor for the late Heath Ledger, who died a year ago today of an overdose of prescription pills.

This year's critics' darling, the indie hit " Slumdog Millionaire," is also expected to perform well in the nominations, especially since it swept the Golden Globe Awards less than two weeks ago.

" Frost/Nixon," "Milk" and "The Curious Case of Benjamin Button" are also top contenders for major awards.

In the acting categories, those favored to receive Oscar nominations include Sean Penn for "Milk," Mickey Rourke for "The Wrestler," Frank Langella for "Frost/Nixon," Kate Winslet for "Revolutionary Road" and "The Reader," and Meryl Streep for " Doubt."

Clint Eastwood fans are hoping the veteran will get an Oscar nomination for lead actor for "Gran Torino," which is shaping up to be the 78-year-old icon's biggest box office hit.

The awards will be given out on Feb. 22 in a star-studded ceremony at the Kodak Theatre in Hollywood and telecast live on ABC. Though the Oscars have been hosted by comedians for the last several years, actor Hugh Jackman will be emceeing the proceedings