Zac Efron took a break from shooting The Paperboy in New Orleans yesterday, heading to a local playground to get in a TRX workout. He joins a newly blond Nicole Kidman, Matthew McConaughey, and John Cusack in the film, based on the bestselling novel of the same name. Zac spent the first part of the Summer kicking back with friends and relaxing on the beach, but last month he also got back to business filming a separate project, Heartland. His buff bod, along with others like Kellan Lutz, Jake Gyllenhaal, and other good-looking guys, will soon be in the running for the title of 2011's Hottest Shirtless Star on PopSugar. For now, though, we're still determining who looks best in their two-piece — don't forget to cast your votes in this year's PopSugar bikini bracket!