Jessica Simpson, Beyoncé and Mary J. Blige are among the hottest singing stars, and they’ve also got some killer bodies. So when "Extra" met up with these sexy divas, we got them to share their secrets to staying rock star fit.

"I do work out to stay lean," "Newlywed" Jessica Simpson told us. "If I work out during the day and do a show, which is another hour and a half of working out, I eat my skittles."

And a sensible Queen Latifah told us, "I try to work out a couple times a week at least. I just try to fit things in when I can and just be consistent with it."

While Beyoncé admitted, "I don’t dream of eating certain things that I used to. And I started running again."

Us Weekly Senior Editor, Caroline Schaefer, told us that Beyoncé’s strenuous fitness routine might surprise you. "Beyoncé works out like crazy to be on tour. She was running six miles a day. She was dancing up to eight hours a day."

Forty-two-year-old rocker Sheryl Crow gets a boost from her world-class athlete boyfriend, Lance Armstrong. "He really keeps her on the workout wagon," Schaefer said.

Gwen Stefani sometimes does pushups on stage, and Schaefer revealed another secret about one hot singer: "Kylie Minogue has been known to go back stage and eat oysters, just a quick protein shot."

But in general, Schaefer told us, rockers will, "Have things like nuts, which is a great protein source, lots of water, fruits and vegetables."

Superstar Mary J. Blige has found success with celebrity trainer, Mark Jenkins. "You’ve got to really want it basically, and Mark, he makes you look incredible when it's over," Blige said.

So it looks like hitting the high notes and hitting the gym makes for a winning combination.