Star of the phenomenally successful television series “Gossip Girl,” Leighton Meester takes her first lead role in a feature film with Columbia Pictures' new suspense thriller “The Roommate.”

Academy Award®-nominated director Christian E. Christiansen (Råzone) crafts a finely tuned tale of madness and role reversal in “The Roommate,” packed with ingenious twists and heart-stopping surprises as Sara (Minka Kelly), a naïve college freshman begins to suspect that her roommate, Rebecca (Leighton Meester) is not what she appears to be.

“Leighton was the first person we cast for this movie,” says Christiansen. “And she is a fantastic actress. The role of Rebecca requires an actress who can go from normal to insane in very little time. Leighton did a lot of research for the role, trying to figure out what kind of person this would be.”

Meester signed on after reading an early draft of the script and speaking to Christiansen at length about the movie he wanted to make. “He was so open to everything,” she says. “It was really fun to watch the process of developing it. Everybody was bouncing ideas off of one another.”

The edge and rawness of Christiansen’s earlier films won her admiration. “His style is not overly manicured,” says Meester. “Christian does what I think of as ‘ninja’ directing. He doesn’t spell anything out. He just plants an idea in your head. Even if it’s not something that’s in the front of your mind, it’s back there, and the wheels are still turning. He conjured as much from me as he possibly could.”

Meester, who has been a successful actress since her early teens, has never been through the roommate experience herself. “Being assigned the person you’re going to live with for the next eight or nine months sounds a lot like a blind date,” she says. “It’s strange to think that when you come to college, you have to live with someone you don’t know at all. The idea of sharing some totally intimate moments with somebody you don’t know that well is disconcerting and a great jumping off point for this story. I think everyone who sees this film will interpret it a little differently. They’ll certainly be scared and intrigued.”

The role made tremendous demands on Meester, both physically and emotionally. “It wasn’t an easy movie to make, but it was always interesting,” she says. “Christian had a very specific vision of how he wanted things, which made me confident that it would turn out beautifully. He’s all about making things as real as possible and getting the most honest performance out of everyone.”

She delved into the character’s psyche, developing a personal history for Rebecca and consulting with psychiatrists to learn more about what makes her tick. “This is the story of the psychological deterioration of a human being who has no real identity of her own and is trying to appropriate another person’s,” she says. “The character has so much depth. I had to find whatever I could in her to love, because I don’t think she means anybody any harm. Her relationship with her parents was particularly interesting.”

At the start of the movie, Rebecca seems like the ideal friend for Sara. “She’s actually a good influence on her,” says Meester. “Rebecca shows Sara all around the city, not just the clubs and parties. But she grossly misinterprets the relationship, which is the beginning of a lot of problems. As they get closer, Rebecca starts to lose touch with reality.”

Opening soon across the Philippines, “The Roommate” is distributed by Columbia Pictures, local office of Sony Pictures Releasing International.