The pop star bares her belly in the new Shape magazine!

So is she or isn't she? ASHLEE SIMPSON is playing coy about those pregnancy rumors, but the singer is showing super-flat abs in a red-hot bikini on the cover of the new Shape magazine, on stands May 5th. Inside, she talks about her new exercise and diet routine.  

"I never thought I'd be on the cover of a magazine in a bikini," the 23-year-old singer tells the mag, but says she couldn't say no after working out two to three times a week with celebrity trainer MICHAEL ALEXANDER. She also sticks to a diet of yogurt and granola for breakfast, turkey or veggie wraps for lunch and lean proteins like fish and chicken for dinner.

"I try to listen to what my body craves," she tells the mag. "Sometime it tells me to eat more fruit, but sometimes it tells me to eat Skittles!"

For more details on her routine, pick up the new issue of Shape!