New York - The marital thriller Obsessed, starring chart- topping pop singer Beyonce Knowles, opened its first weekend in cinemas in first place on the North American box-office rankings, according to preliminary studio estimates issued Sunday.

The movie rang up 28.5 million dollars in revenue from Friday- Sunday.

In the film, Knowles finds herself threatened by a woman who becomes obsessed with her husband, after being hired as a temporary worker at the man's office.