'The Roommate' topped the North American box office this weekend.

The low-budget thriller – starring 'Gossip Girl' actress Leighton Meester – took $15.6m between Friday (04.02.11) and Sunday (06.02.11) beating 3D adventure film 'Sanctum' and Ashton Kutcher comedy 'No Strings Attached'.

Telling the tale of a college student who is obsessed with her roommate, the top-grossing film – which has been panned by critics - also beat 'The Green Hornet' and 'The King's Speech'.

Overall cinema takings dropped because of the Super Bowl, with this week's top 12 films grossing $75 million – 18 per cent less than last weekend, according to box office analysts Hollywood.com.

The NFL showpiece game is America's biggest annual TV event, but females under the age of 21 are less likely to watch it – and it was this demographic which accounted for two-thirds of the 'The Roommates' audience, according to its distributer.

Box office figures are also down 24 per cent on the same weekend last year, when romantic drama 'Dear John' topped the chart ahead of James Cameron's 'Avatar'.