#20 to #11 20: Adam Levine The Maroon 5 frontman can hold a note just as flawlessly as he can hold a yoga pose. He recently told Men's Health, "Yoga has given me the ability to be more focused and make better decisions that come from a clearer place." And the killer muscle definition that comes with it is definitely a bonus. 19: Liam Hemsworth Liam's super-fit body is undeniable (unlike those constant breakup rumors about him and fiancé Miley Cyrus). The Australian actor—whose brother also appears on our list—told Men's Health how he slimmed down to play a starving character in The Hunger Games with a strict training regimen and a variation on the Paleo Diet, which helped him drop 20 pounds the month before filming. 18: Chris Pine The 32-year-old action star isn't planning to slow down anytime soon. As he's headlining the Star Trek franchise, Chris is also starring as a CIA analyst in the upcoming movie Jack Ryan, out later this year. And lucky for us, those Star Trek outfits are pretty tight. 17: Ryan Gosling Emma Stone probably put it best in the movie Crazy Stupid Love when she told Ryan, "Seriously? It's like you're Photoshopped!" We couldn't agree more. Check out more of Hollywood's hottest washboard abs. 16: Bradley Cooper You would think that a guy who parties on screen for a living might be sporting more of a beer gut than a six pack. But the star recently told Men's Health UK that he stays fit with supersetting exercises and a strict diet. 15: Zac Efron The actor—and his abs—have come a long way since those High School Musical days. Zac debuted a bulkier body for his role as a marine in last year's The Lucky One, and we've been impressed ever since. 14: Ryan Reynolds It's hard to decide what we love more about Ryan—his amazing body or his hilarious sense of humor. Luckily, most of his acting roles show off both. 13: Taye Diggs The actor is constantly photographed hanging out with his wife Idina Menzel and their son Walker, but don't assume this super-fit guy has gone soft: he recently chased down a burglar who broke into their house while they were at the SAG Awards this year, and—get this—detained him until police arrived, according to Us Weekly. Now that his show Private Practice has finished, we're hoping to see more him (and his awesome body) on the big screen. 12: Mario Lopez Who knew that Slater from Saved By the Bell would be even hotter and fitter twenty years later? Now the actor and television host has made fitness part of his career with his books Extra Lean and Mario Lopez Knockout Fitness. And we're guessing it doesn't take much more than a full-body shot of Mario to advertise for those. 11: Ian Somerhalder One look at Ian's bulked-up arms, and there's no question why vampire mania is still going strong. The star of The Vampire Diaries also heads the Ian Somerhalder Foundation, an environmental activism group raising awareness about everything from deforestation to animal cruelty. Swoon.