"Extra's" Terri Seymour caught up with Black Eyed Peas singer Fergie during her glamorous photo shoot for her new Voli Light Vodka -- and asked her how she stays in such great shape.

"I do a lot of treadmill, sometimes I'll just do dancing," said Fergie. "I like to mix it up."

She does admit she will cheat every so often. "Once in awhile, I go out to dinner with [husband] Josh [Duhamel] and cheat a little bit. I always let myself have a little bit of fun."

As the new owner of Voli Light Vodka, Fergie is excited. "It's finally here, people -- the first low-calorie vodka!"

Check out more of our interview!