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Martial arts flick 'The Forbidden Kingdom' conquered the box office this weekend, taking in $20.9 million for first place, according to preliminary studio estimates.

The action film marks the first big screen pairing of martial arts superstars JACKIE CHAN and JET LI. The film follows an American teen who is transported back in time to ancient China, where he must aid a group of warriors in freeing the Monkey King.

Premiering in second was JUDD APATOW's latest offering, 'Forgetting Sarah Marshall,' which made $17.3 million. The comedy stars JASON SEGEL (who also wrote the film) and KRISTEN BELL in the story about a guy whose girlfriend leaves him for a rock star. MILA KUNIS, JONAH HILL, BILL HADER, PAUL RUDD, JASON BATEMAN, JACK McBRAYER and WILLIAM BALDWIN co-star.

'Prom Night' dropped to third with $9.1 million. The remake of the 1980 JAMIE LEE CURTIS film of the same name stars BRITTANY SNOW as a teenager whose dream of the perfect prom is ruined when a madman (who had previously stabbed her entire family to death) joins the party.

AL PACINO's '88 Minutes' debuted in fourth with $6.8 million. In the film, Pacino plays a college professor whose past catches up with him when he receives a death threat claiming he has only 88 minutes to live. The film co-stars ALICIA WITT, LEELEE SOBIESKI, AMY BRENNEMAN, DEBORAH KARA UNGER and NEAL McDONOUGH.

JODIE FOSTER and ABIGAIL BRESLIN's fantasy adventure, 'Nim's Island,' fell to fifth with $5.7 million.