Jordin Sparks tweeted a pic of her new figure in a bikini. - Twitter.comThey say when you've got it, flaunt it. And that's exactly what "American Idol" winner Jordin Sparks did --- to her 871,277 Twitter followers.

The 21-year-old tweeted a picture of herself in a strapless polka-dot bikini, along with the comment, "I don't know why but my bathing suit reminds me of fruity pebbles. :)"

But it wasn't the cerealesque bathing suit that stunned fans -- it was her newly toned and slimmed-down figure.

"Something just clicked with me, and instead of sitting around talking about it I said, 'I'm going to go hike that mountain!' And it continued. I've been hiking and I've done a couple of runs," she told Us Weekly last month. "I also do Zumba. It's so much fun!"

And it clearly worked! Though the singer, who'll tour with NKOTBSB this summer, never shared how much weight she wanted to lose, she did reveal who inspired her to do it -- Halley Berry.

"She is perfect! I think she is beautiful. For me being 21, and then seeing Halle Berry look as good as she does, I

Nina Dobrev shares her fitness regimen with Seventeen. - SeventeenThe 22-year-old admits she prefers volleyball over beach lounging. - Seventeen

If Nina Dobrev, the svelte star of the hot CW series"Vampire Diaries" keeps her own diary of how she manages to maintainthat fab figure, we want a copy. But the interview the 22-year-old Bulgarianborn beauty gives to Seventeen magazine comes pretty close.

Watch the Behind-the-Scenes Video of Nina's Shoot!

"I do a lot of yoga. I practice yoga three or fourtimes a week. It's an escape for me," says Dubrev, who may just have acareer to fall back on if if this whole acting thing doesn't work out. "Icould be a yoga instructor. I'm not certified, but I could do it. Once I did aclass where the instructor didn't show up, and I just went to the front and didit, and everyone followed. So I've done it before, and I love it."

Meet the Guys from 'Vampire Diaries'

And when she can't make it to the gym, the Bulgarian-bornbeauty still squeezes in plenty of activity to keep fit.

When she can't work out, Nina keeps busy with plenty of other activities. - SeventeenThe lucky actress says she get caught up in counting calories. - Seventeen

"Over Christmas, I had a break, and I didn't go tothe gym once, but I was in better shape than I am now, because for the

Stressful, busy days can make it difficult to shut out the world and get some shut-eye, an issue millions of Americans deal with nightly. Plenty of celebs, including Drew Barrymore and Eminem, have admitted to battling insomnia and even teen queen Miley Cyrus recently tweeted, "I have just diagnosed myself. I am an insomniac."

Whether you're in show biz or not, any kind of hectic schedule can leave you physically exhausted, but still mentally stimulated. After getting medical treatment for insomnia in 2008, "Grey's Anatomy" star Justin Chambers told People magazine, "Your mind keeps racing, and your body is tired. It wants to go to sleep, but it can't."

Eminem has spoken publicly about his battle with insomnia. - Deano/Splash NewsMiley Cyrus recently tweeted, "I have just diagnosed myself. I am an insomniac.” - PacificCoastNews.com

Though you might want to reach for that sleeping pill to knock yourself out, there are more natural ways to get some rest. Nutritionist Kelly Aronica shared some tips — including foods to reach for and ones to avoid — on how to ease yourself into a gentle and peaceful slumber without the morning grogginess of sleeping pills.

The voluptuous Kim Kardashian doesn't rely on diet alone to keep her curvy physique in shape. In addition to regularly hitting the treadmill, the reality star's workout weapons include doing plenty of squats, lunges, and abdominal exercises. Celebrity trainer Gunnar Peterson tells us which moves Kim and other curvaceous clients, like Jennifer Lopez and Sofia Vergara, use to stay svelte in all the right places on this episode of "Inside & Out."

More Celebrity Features on Yahoo!:
Gwyneth Paltrow Shares Her Sculpting Secrets
Cindy Crawford's Body Balance Tips
Kim Kardashian: I Didn't Know 'How to Embrace Curves' as a Kid

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Cindy Crawford - Ralph Notaro/Splash NewsFormer supermodel Cindy Crawford was famous for her curves and for her signature beauty mark in the 1980s. Now 45 and married with two kids, Crawford still puts women half her age to shame. omg! caught up for an exclusive chat with the multi-talented mom -- who just signed on as the new face of Propel Zero enhanced water -- about health, fitness, and family.

The Propel Zero ad you did with your husband Rande Gerber, and kids, Presley, 11, and Kaia, 9, was really cute. Did your kids really ask to be in it the night before? "100%! I was like, Rande, you have to do it because everyone knows what you look like, but we could have some fake kids -- real kids, just not my kids -- and we won't show their faces so they could kind of pass as my kids. Then the night before we were all out for dinner, and the kids were like, 'You're using fake kids? We don't want you to use fake kids.' It was a Sunday, so they didn't have school, and it ended up being a really nice family day. They ended up

"Biggest Loser" trainer Bob Harper isn't shyabout letting the world know he's taking Jillian Michaels departure from thereality show pretty hard. "Do you want meto start crying in my house?" he responded after "AccessHollywood" asked him his thoughts on starring in the reality show withoutMichaels, who announced in December that this season will be her last.

Harper admitted he doesn't like change and being withoutJillian will be a really big adjustment, joking, "Jillian Michaels isabandoning me!"

During the interview, the 45-year-old fitness expert alsotalked about how he believes he was put on Earth to help others lose weight andget healthy, and revealed the unlikely contestant he believes has been theshow's greatest success.

Watch the full interview here:

Allison Sweeney's Tips to Shedding the Baby Weight
Cindy Crawford's Body Balance Tips
Gwyneth Paltrow Reveals Her Fitness Secrets

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Gwyneth flaunts her fab figure on the red carpet. - Jon Kopaloff/FilmMagic.comIt's hard to believe that Gwyneth Paltrow, with her tonedand tight bod, just wrote a cookbook filled with recipes like oyster po' boys,challah French toast, and cheesy stuffed burgers. (Sure, there are healthieritems in the book, too, but we like to skip right to the good stuff.) If the38-year-old mother of two manages to eat decadent dishes like thoseand stay so lean and mean, then, well, I'm jealous.

But onething everyone knows the actress focuses on to stay in svelte shape is exercise.Gwyneth's trainer Tracy Anderson shared a few moves from the actress' workoutroutine for achieving sculpted arms and flat abs with Self.com. You may end upwith more muscles, but we can't promise the Oscar or rock star husband ...

Gwyneth's Sexy Arm Sculptor, works arms, shoulders, waist, and back

Step 1: Stand with legs together, elbows bent and palms touching.

Step 2: Bend left elbow, reaching toward center of back, andextend right arm overhead, palm forward. Return to start for one rep.

Mark Abrahams/SelfGwyneth Paltrow has been busy making the rounds promoting her new cookbook, My Father's Daughter: Delicious, Easy Recipes Celebrating Family & Togetherness. Yes, it's totally annoying that Gwyneth seems to be constantly telling us (via her website Goop.com) how we'd all be much better people if we could just be more like her, but is it really her fault that -- as her mother Blythe Danner says -- "she is so damn good at everything she does"?

In the May issue of Self, Paltrow shares an excerpt and a few supposedly yummy-yet-healthy recipes from her book. The Oscar winner, 38, also reveals how she maintains her fab physique and why she believes she's in the best shape of her life -- even after having two children!

Gwyneth Paltrow's Cardio Playlist

"I never thought that I'd be considered to have a good body," she admits. "I was bony up top and kind of dumpy on the bottom. But my trainer, Tracy Anderson, completely changed my legs, butt, arms, and stomach. I feel better than ever, too."

So