The Associated Press

Movie-goers were easy prey for a double dose of space invaders.

The sci-fi smackdown Alien vs. Predator, featuring the creatures of the Alien and Predator franchises, debuted as the No. 1 weekend movie with $38.25 million.

Princess Diaries 2: Royal Engagement, with Anne Hathaway and Julie Andrews reprising their royal roles, opened in second place with a three-day gross of $23 million, pushing its total since premiering Wednesday to $37.2 million.

That was close to the $37.9 million The Princess Diaries made in its entire first week in August 2001.

The new movies bumped Collateral, the previous weekend's top film, to third place with $16 million.

The animated kid flick Yu-Gi-Oh! The Movie, adapted from the TV cartoon show from Japan, debuted at No. 4 with $9.4 million.

Alien vs. Predator eclipsed the $36.4 million debut of last summer's horror hybrid Freddy vs. Jason, which paired the slashers of the Friday the 13th and A Nightmare on Elm Street franchises.