In the superficial world of Hollywood, few things are as important as a rock-hard body.
And while it may seem like celebrities are all just genetically blessed, the truth is most of them have to work their rich little butts off to keep in tip top shape.
Check out some of your favorite stars huffin and puffin as they try to work off the carrots and water they just ate.
<b>Ryan Seacrest</b>
The "American Idol" host runs in Beverly Hills with his trainer.
Wonder if he ever works out to music from "American Idol" hopefuls?
For more pics of Ryan, go to <a href="http://www.x17online.com/celebrities/ryan_seacrest">x17online.com.</a>
<b>Charlize Theron</b>
The Oscar-winner takes a break in between sets on the benches. (Stefan/X17online.com)
<b>Ryan Phillippe </b>works out in Beverly Hills.
He told Men's Health in May: "My aim is always to progress -- to make better decisions and be a better father, a better boyfriend, a better husband if it happens again, a better friend, a better actor. My goals are to improve in all areas of life."
For more pics of Ryan, go to <a href="http://www.x17online.com/celebrities/ryan_phillippe">x17online.com.</a>
<b>Sandra Bullock</b>
The Oscar winner still finds time to hit up her gym in Huntington Beach, even with little Louis at home.
“I do Pilates, kickboxing, weight training," she says. "When I’m in Austin, I run or ride a bike. If I can work out every day, I will.”
For more pics of Sandra, go to <a href="http://www.x17online.com/celebrities/sandra_bullock">x17online.com.</a> (X17online.com)
<b>Tom Brady</b>
The Patriots Quarterback boxes at a gym in Los Angeles while Gisele is probably out somewhere with their son, Benjamin.
For more pics of the QB, go to <a href="http://www.x17online.com/celebrities/tom_brady">x17online.com.</a>
(X17online.com)
<b>Reese Witherspoon</b>
The Oscar winner loves to sweat it out at her local gym.
"I try to exercise every day. I like to run for about an hour, and I'm big into working out with girlfriends," she has said.
For more pics of Reese, go to <a href="http://www.x17online.com/celebrities/reese_witherspoon">x17online.com.</a> (X17online.com)
<b>Matthew McConaughey</b>
Talk about multi-tasking!
McConaughey reads a script while pedaling away on a stationary bike. Sources say he stayed on the bike for over an hour.
Must have been a good script.
For more pics of Matthew, go to <a href="http://www.x17online.com/celebrities/matthew_mcconaughey">x17online.com.</a> (X17online.com)
<b>Meg Ryan</b>
The actress, who doesn't have any films lined up, enjoys to jog during her free time.
"I've been famous since I was a teenager. There are a lot of empty spaces in that. I just feel like I've been filling in the cracks a little bit. I feel very fortunate, very free," she says.
For more pics of Meg, go to <a href="http://x17online.com/celebrities/meg_ryan">x17online.com.</a>
<b>Marlon Wayans</b>
Marlon hasn't done a movie in a while, but he likes to tone his body by lifting weights an doing cardio.
For more pics of Marlon, go to<a href="http://www.x17online.com/celebrities/marlon_wayans"> x17online.com.</a>
<b>Kate Hudson</b>
The sporty actress is always doing something athletic to keep her body trim.
And in her upcoming flick, "The Killer Inside Me," Hudson leaves nothing to the imagination.
"I’m pretty comfortable with my body," she says of going nude on film. "I’m imperfect. The imperfections are there. People are going to see them, but I take the view you only live once."
For more pics of Kate, go to<a href="http://www.x17online.com/celebrities/kate_hudson"> x17online.com.</a>
<b>Jason Biggs</b>
The "American Pie" star is looking thin as of late. Could be all the jogging he's been doing around Beverly Hills.
For more pics of Jason, go to <a href="http://www.x17online.com/celebrities/jason_biggs">x17online.com.</a>
(X17online.com)
<b>Amanda Seyfried</b>
You don't get legs like that by sitting around!
The "Dear John" star often takes her dogs for hikes in Runyon Canyon.
"I have to stay in shape because I'm an actress," Seyfried has said. "It's f**ked up and it's twisted, but I wouldn't get the roles otherwise. If I'd been bigger, I don't think they would have cast me for Mamma Mia!"
This is probably true...
For more pics of Amanda, go to <a href="http://www.x17online.com/celebrities/amanda_seyfried">x17online.com.</a> (IONU/X17online.com)
<b>Ben Stiller</b>
The funnyman took advantage of the warm spring weather by taking his workout outdoors to Runyon Canyon.
For more pics of Ben, go to <a href="http://www.x17online.com/celebrities/ben_stiller">x17online.com.</a> (X17online.com)
<b>Liv Tyler</b>
“I recently got a hula hoop," says Tyler. "I put my favorite song on and stand outside and hula hoop in every direction until the song is over and I’m all out of breath. It’s really fun.”
For more pics of Liv, go to x17online.com/celebrities/liv_tyler
<b>Jeremy Piven</b>
The "Entourage" star knows that Ari Gold has to look his best so he does everything from running to yoga.
"The reality is that I'm not a professional athlete, and I'm not a ripped-up piece of steel," Piven explains.
He tries different things to stay fit. He says, "I'm just trying to find what's right for me."
For more pics of Jeremy, go to <a href="http://www.x17online.com/celebrities/jeremy_piven">x17online.com.</a> (X17online.com)
<b>Fergie</b>
The fit singer goes for a run in Bel Air.
You think she has Black Eyed Peas hits blaring from those headphones?
For more pics of Fergie, go to <a href="http://www.x17online.com/celebrities/fergie">x17online.com.</a> (X17online.com)
<b>Gilles Marini</b>
The "Brothers & Sisters" heartthrob knows what the ladies like so he works out his chest at an LA Fitness.
"Maybe when I'm 73 years old, I won't have to worry about being a sex symbol anymore," he says. "I can't say, 'Oh, my God, I don't want to be a sex symbol.' I am what I am."<br><br>
For more pics of Gilles, go to <a href="http://www.x17online.com/celebrities/gilles_marini">x17online.com.</a>
<b>Felicity Huffman</b>
The "Desperate Housewives" star is often seen jogging with hubby William H. Macy in L.A.
Last year she and co-star Teri Hatcher participated in the Malibu Triathlon.
For more pics of Felicity, go to <a href="http://www.x17online.com/celebrities/felicity_huffman">x17online.com.</a>
<b>Jerry O'Connell</b>
Rebecca Romijn's hubby sweats it out with their adorable pooch, Better.
For more pics of Jerry, go to <a href="http://www.x17online.com/celebrities/jerry_oconnell">x17online.com.</a> (X17online.com)
<b>Lisa Rinna</b>
"I exercise at least 4 days a week," says the former "Dancing with the Stars" contestant.
"I try to mix it up: I do yoga. I run or do Spinning. I also do cardio bar, cardio combined with ballet and weight lifting. Doing those dancer pliés really tones your legs," she says.
For more pics of Lisa, go to <a href="http://www.x17online.com/celebrities/lisa_rhinna">x17online.com.</a> (X17online.com)