13 Abs-olutely Sexy Stars of Summer

NICK JONAS

Look who's all grown up! The youngest Jonas took to Instagram July 30 to show off the positive side effects of eating well and exercising. "I never do this but... Healthy living and fitness update," he wrote, calling the snap a "Post workout picture."

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13 Abs-olutely Sexy Stars of Summer

SHAKIRA

Less than a year after welcoming son Milan, The Voice judge bared her rock-hard midsection for the September cover of Self magazine and revealed that she began getting back in shape when her son was 2 months old. "Two minutes of ab work isn't enough," she said, going on to describe her diet as eight small meals a day, between 200-250 calories each, and consisting of lots of fiber, protein, calcium, iron and fish oil.

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13 Abs-olutely Sexy Stars of Summer

KELLY ROWLAND

The X Factor judge proved her body is her best advertisement when she showed up on the set of her new workout video, Sexy Abs Cardio Sculpt, with a serious six-pack. "I did this whole workout for an hour, five days a week, to prepare," she told PEOPLE. "It is intense while you're doing it. But when you're done you feel incredible."

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13 Abs-olutely Sexy Stars of Summer

JENNIFER ANISTON

"When I really wanted to have a cheat day, I had to have a kale chip," Aniston said of the strict diet that helped her get into stripper shape for her nearly naked role in We're the Millers. "I was on a very like, you know, greens and vegetables and lean proteins and kale."

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13 Abs-olutely Sexy Stars of Summer

ANDY MURRAY

Wimbledon's reigning champ is a stud on and off the court! Murray went sexy and shirtless for a July 15 trip to the beach in the Bahamas.

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13 Abs-olutely Sexy Stars of Summer

CHRIS PRATT

The Parks & Recreation actor traded one six-pack for another to play an alien in the upcoming Guardians of the Galaxy. "Six months no beer," he captioned his impressive transformation on Twitter July 6, adding, "My brother made me post this."

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13 Abs-olutely Sexy Stars of Summer

LADY GAGA

A year after the singer showed off a curvier figure, having gained 25 lbs., Gaga returned to fit form, and flaunted her hot figure with a body-baring stroll through N.Y.C. on July 11.

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13 Abs-olutely Sexy Stars of Summer

MATT DAMON

Getting ripped for Elysium was no easy matter for Damon, who hit the gym four hours a day. "It was really hard because I love to eat and drink!" he told PEOPLE. "It's very hard to motivate me to get in shape."

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13 Abs-olutely Sexy Stars of Summer

ORLANDO BLOOM

It's definitely no shirt, no problem for Bloom, who beat the heat in New York on July 16 by doffing his top.

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13 Abs-olutely Sexy Stars of Summer

NAYA RIVERA

Even in a high-waist skirt, there's no hiding the Glee starlet's amazing abs, which peeked out of her ensemble before her July 30 appearance on Jimmy Kimmel Live in Hollywood.

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13 Abs-olutely Sexy Stars of Summer

DANICA MCKELLAR

Winnie Cooper, is that you? Abs-olutely! The former Wonder Years actress displayed a tiny waist and toned midsection while filming Avril Lavigne's new music video for "Rock N Roll" on July 25.

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13 Abs-olutely Sexy Stars of Summer

RYAN LOCHTE

The swimming stud never misses an opportunity to showcase his rock-hard build, and July 19 proved no exception when Lochte posted a photo with his coach Jack Roach to Instagram during training.

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13 Abs-olutely Sexy Stars of Summer

NICOLE RICHIE

Having two children hasn't stopped Richie from daring to bare – and putting others to shame – during a bikini-clad July vacation in Cannes, France.

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13 Abs-olutely Sexy Stars of Summer

RIHANNA

Never one to be shy about her body, the songstress let her taut tummy take center stage during an otherwise covered-up evening out in London July 19.

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13 Abs-olutely Sexy Stars of Summer

KELLAN LUTZ

From the looks of it, channeling a Greek god has done Lutz's body good, as the Twilight star let his trim torso speak for itself on Hercules 3D's Bulgarian set in July.

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