Celebrity Sexy, Single – and Shirtless! The heat is on, but their shirts aren't! Check out the treasure chests of Brody, Mario, Zac and more! By People Staff Published on June 11, 2008 05:00 PM Share Tweet Pin Email Trending Videos 01 of 10 BRODY JENNER PV/Flynet Birds of a feather flock to the Hills star, who showed off his lean, mean torso on a family vacation in Hawaii. (Hmm ... Wonder if he puts his name on his underwear as well?) 02 of 10 BRANDON JENNER Will Binn/ Pacific Coast News Brody's older brother gets something off his chest – his shirt! – revealing a matching "Jenner" tattoo while on their Hawaiian vacation. 03 of 10 JOHN STAMOS Will Binns/ Pacific Coast News Paging rippling pecs – STAT! The ER doc gets hearts palpitating during a kayaking trip on a Hawaiian beach. 04 of 10 ZAC EFRON Fame Pictures At 20, he's too young to drink, but that doesn't stop the actor from bringing his own six-pack to the Utah set of High School Musical 3. 05 of 10 CHRIS CARMACK Will Binns/ Pacific Coast News The Into the Blue 2 star grins and bares it during a wet and wild day in the Hawaiian surf. 06 of 10 JOHN MAYER Will Binns/Pacific Coast News Is he sure his hit single wasn't called "My Body Is a Wonderland?" The singer unveils his tattooed torso while boogie boarding – where else? – in Hawaii. 07 of 10 ANDY BALDWIN Louise Barnsley/ Pacific Coast News The Bachelor star flexes his muscles during a beachside game of football in Hawaii. 08 of 10 DAX SHEPARD Ramey The funnyman proves he's a tattoo all-star – and fan of stomach crunches – while filming in Manhattan. 09 of 10 ANDRE BIRLEANU Gabriel S/ Bauer-Griffin The America's Most Smartest Model hunk makes a pec-tacular showing while shopping – presumably for a shirt – on L.A.'s Melrose Avenue. 10 of 10 MARIO LOPEZ Kadena Pix/ Bauer-Griffin The A Chorus Line star unveils his impressive body of work while catching some rays on a Miami beach.