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Alo-ha! The High School Musical star, 22, graduates to sex symbol – and tops PEOPLE's list – after showing off his ripped form in the Hawaiian surf recently. "My fail-safe is to go to the gym for an hour," the actor, who appears (shirtless!) in the summer drama Charlie St. Cloud, has said.
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With the birth of Hank Baskett IV came "curves [that] shocked me big-time," the E! reality star, 25, admitted to PEOPLE. So two months ago, Wilkinson (in Malia Mills) kicked into gear. "I want to wear skimpy clothes again and show off my hot little body."
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Fans are used to seeing ... ahem, a little more of the Eclipse star, 25, in his CK underwear ads – not that he minds. "I won't lie about it," says the actor, who trained and stopped eating candy to shape up for the shoot. "I started getting text messages ... people were always commenting on the billboard and asking for pictures for their daughters."
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It's hard to believe the reality star once felt insecure about her figure. "Everyone talks about this great butt I had, but I was so unhappy about it," says Kardashian, 29, who told PEOPLE in '09 that by 11 she had developed "huge boobs and a butt." Now she works out regularly and curbs her junk-food cravings, saying, "I love my curves ... I'm proud of my body."
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Hello, washboard abs! The MacGruber star showed off his seriously buff physique on the cover of Men's Health in May, proving that at 35 he's got just as much flex appeal as Hollywood's twentysomethings. His motivation? "I want to throw my kids up in the air and wrestle them."
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There is nothing down-home about this Grammy winner's killer bikini body, and thanks to a regimen of healthy eating and regular workouts (cardio, kickboxing and the elliptical), the longtime vegetarian lost – and has kept off – 20 lbs. following her season 4 win on American Idol in 2005.
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You want body language? Talk to The Situation, whose stomach-baring move has "blessed" him with "international popularity." "I have always had an unbelievable six-pack," says the Jersey Shore star, 27, who calls keeping fit "the key to my success."
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To star opposite Tom Cruise in a summer action movie, you'd better be in the shape of your life. Thankfully, at 37, his Knight and Day costar is "a genetic goddess," her trainer Teddy Bass says. Diaz does a mix of Pilates, plank exercises and leg pulls to keep her 5-ft., 9-in. frame lean and mean.
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JENNIFER LOVE HEWITT
"I ordered a string bikini for the first time since I was 16," says the actress (in Betsey Johnson), 31, who faced seeing unflattering bikini photos of herself plastered across the web in 2007. Looking back, she tells PEOPLE, those photos "did something good for me in the long run. Now I'm a much healthier eater and I love exercising."
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What does the Grammy-nominated rapper have in common with his rumored ex, tennis champ Serena Williams? A killer body. The Chicago native, 38, made Men's Fitness magazine's Top 25 fittest men in the world (alongside athletes like soccer stud Cristiano Ronaldo). "I feel like I'm planting seeds when I'm [working out]," he says, "making things fruitful and giving back to myself."
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With her tongue-in-cheek music and pin-up good looks, Perry isn't your typical California Gurl. No wonder Maxim named her No. 1 on their 2010 Hot 100 list. How did the 25-year-old top the likes of Megan Fox? She's "the rad chick who taught you how to skateboard and whistle and also looks unbelievable in a bikini," the magazine explained.
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The Transformers star once famously told Esquire, "I'm just really confident sexually, and I think that sort of oozes out of my pores." While the 24-year-old has topped plenty of hot lists, she says deep down she's really a stay-at-home nerd. "We watch a lot of Discovery Channel and TLC," she told Allure of life with boyfriend Brian Austin Green.
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Summer's hottest action figure? Look no further than the Prince of Persia star, whose ripped torso and bulging biceps created buzz months before the movie hit theaters. Joking, "It was so much fun to get paid to get tanned and get in shape," Gyllenhaal, 29, got into the best shape of his life doing the French martial art of Parkour.
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Even this Hills babe, who's often snapped in her two-piece (here, in Melissa Odabash), wishes for, yes, a better bikini body. "I've always had a good stomach," says the reality star, 25, "but I wish I had longer legs." To make the most of her assets, she hikes or boxes twice a week, and for an added boost, drinks daily wheatgrass shots "even though they don't taste good."