Just in time for summer 2008, she talks to Shape magazine about finding the confidence to put on a bikini.

Ashlee Simpson has seen her name splashed in the tabloids over the years for various reasons: her weight, her romantic relationships, did she or didn't she have a nose job? But the cheerful 23-year-old singer doesn't let gossip bother her. "This last year has been about finding strength within myself—not looking to others for it."

Over the past year, Ashlee's seen a real change in her body. "I started working out more, which really helped me tone up," she says. She ramped up her exercise routine with L.A. celebrity trainer Mike Alexander. With two or three one-hour sessions per week, Ashlee is achieving her goal of having a powerful yet feminine body. "Exercising makes me feel stronger and sexier," she says. "It just makes my whole day better. I have more energy to perform, my head is clearer—which helps me write my lyrics—and I sleep better. What more can you ask for?"

While her sister, Jessica, is known for wearing curve-revealing outfits, Ashlee Simpson's style has been a more covered-up rocker look. Who knew the hoodies and baggy cargo pants were hiding this body?! Ashlee has been training with Mike Alexander, owner of MADfit, a private training studio in Beverly Hills (he's best known for making Jessica Simpson look fabulous in her Daisy Dukes). The two usually work out at Ashlee's home, where she has a treadmill, an elliptical, and dumbbells. "I love it when my arms are toned, so we use weights to target them—and we do lunges to give my small butt more shape," she says. Alexander also devises moves that don't require any tools but do utilize Ashlee's surroundings. "Her backyard has about 30 to 40 steps, so I have her jog down, do lunges for the length of the pool, jog back up the stairs, then do a set of squats," he explains. "It's the kind of workout you can easily modify depending on where you are because hotels, office buildings, and homes usually have stairs." Ashlee's dance background has given her incredible balance and coordination, which she needs for performing, but sometimes she has a hard time focusing, so I try to change things up frequently," says Alexander. "Circuit-style sessions are perfect for that." We asked him to give us a typical Ashlee workout that anyone can do at home. His high-energy plan (all you need are some steps or a bench, a pair of 5- to 7-pound weights, and a jump rope) incorporates tri-sets, three back-to-back moves that work your upper and lower body.