The first-time director and cast of unknowns of the acclaimed sci-fi thriller "District 9" have given Hollywood a late-summer box-office boost.

The Sony release produced by "Lord of the Rings" director Peter Jackson led the weekend with a $37 million debut, according to studio estimates Sunday.

"District 9" is the debut feature from commercial and music-video director Neill Blomkamp, who co-wrote the tale about extraterrestrials forced by humans to live in squalor in a ghetto in South Africa.

The previous weekend's No. 1 movie, Paramount's "G.I. Joe: The Rise of Cobra," slipped to second place with $22.5 million, raising its 10-day total to $98.8 million.

Another sci-fi tale, the Warner Bros. romance "The Time Traveler's Wife" starring Eric Bana and Rachel McAdams, opened a solid No. 3 with $19.2 million. The film joined the previous weekend's "Julie & Julia" as a choice for women, with females accounting for 76 percent of its audience.