Kellan Lutz reallllly likes taking off his shirt -- and it's pretty easy to see why.

The "Twilight" star shows off his incredibly sculpted body in the brand new GQ Style Australia, where he talks about his outdoor workout regime.

"I get bored working out inside, so the beach has been my place lately,” he says. “I run, I swim, I play paddleball, basketball, do some mixed martial arts. I like mixing things up.”

Lutz can actually be seen doing his intense routine at Venice Beach, often photographed there by the paparazzi ... shirtless, naturally.

Other interesting tidbits from the interview: He's a size 12 shoe and actually lives with a bunch of roommates -- one of which he found on Craigslist!

“I posted an ad on Craigslist saying I was looking for new blood," he says. "Dick came by and we liked him, so, yeah, now he’s one of my boys.”

Check out the hot shots above and some behind-the-scenes video from the shoot below.