Get ready to say goodbye to Gossip Girl as we know it.

The show’s not closing shop just yet, but Leighton Meester tells me she already knows when she’ll be exiting the hit prime-time soap…

“Two more years,” she told me yesterday at the Four Seasons in Beverly Hills, while promoting her new movie, Country Strong.

Why then? “Because we’re under contract,” she said matter-of-factly.

While Meester said she “obviously enjoys working on the show and living in New York,” she also explained that producers and the network have been more understanding than ever before about Leighton and her costars taking time off or jiggering schedules in order to pursue other projects, particularly movies. “It allows you to be ready for when the show’s over,” she said.

Will the entire series end in two years, too? “I don’t know,” Meester said, “but I think there’s that old saying about wanting to go out on top.”

In Country Strong, Meester costars as Chiles Stanton, a singing beauty queen seen as a threat by Kelly Tanner (Gwyneth Paltrow), a rehabbing alcoholic country singer trying to make a comeback under the watchful eye of her manager husband (Tim McGraw). Tron star Garrett Hedlund is Beau Hutton, the hot as heck rough-around-the-edges musician who befriends both Kelly and Chiles.

The movie hits theaters on Jan. 7.

“You know, it’s good to look in the mirror and not totally recognize yourself,” Meester said of playing the country cutie. “You know, she’s got big hair, big eyelashes, acrylic nails, lip liner, blue leather dresses. It was a lot of fun. It was like playing dress up Country Barbie.”

Meester will also be seen in upcoming flicks like Monte Carlo opposite Selena Gomez and Glee’s Cory Monteith, Oranges with Hugh Laurie and The Roommate, a thriller with Burlesque Twilight hottie Cam Gigandet and Minka Kelly.

Will Gossip Girl mean the end to regular series television for Meester? “Um, I never say never,” she said. “It would have to be the right show just like it would have the right movie.“