Credit: Mario Testino/Vogue

Casper Smart is one lucky fellow.

The 25-year-old choreographer's love of six months, Jennifer Lopez, flaunts her stunning figure in a photo shoot for the June issue of Vogue (on newsstands May 22).

In one of the images (shot by Mario Testino), the American Idol judge, 42, soaks up some rays on a diving board, clad in a skimpy, strapless black monokini--which barely covers her world-famous booty.

Recently, Lopez has turned to celebrity fitness guru Tracy Anderson to keep her stage-ready.

When the busy mom of twins Max and Emme, 4 (with ex-Marc Anthony) is pressed for time, "We skip dance cardio, since she's always rehearsing, and do legs and arms," Anderson tells Us Weekly about the star's routine.

During her trainer's tough workouts the pop star also depends on high-energy tunes, like Katy Perry, to keep her going. "She's dedicated!" Anderson raves.