VIDEO: Leighton Meester is a Creeper in 'The Roommate'

Leighton Meester is taking her bad girl act to the big screen and starring as a creeper in the thriller The Roommate.

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In the film, Leighton (Rebecca) appears to be a sweet roommate to Minka Kelly (Sara) at college.

But after Minka meets Cam Gigandet (Stephen) it appears that something snap and she turns into a crazy person who even pulls out the bellybutton ring of Minka's friend, Alyson Michalka (Tracy)!

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Watch the scary trailer below!