09/15/2011 at 12:50 PM EDT
He's been getting a lot of attention for his fluctuating body mass, but Gerard Butler says his recent weight loss
is easily explained.
"I'm prepping for a surf movie," Butler, 41, told PEOPLE at a Machine Gun Preacher
screening Tuesday in New York. "So I'm surfing every day for Mavericks
For the role of mentor to surfer Jay Moriarity, Butler is combining his daily water sports with a cardio regimen and yoga, the tanned (and toned) star told E!
Not to worry, fans of his physique for 300
can have hope that the action star will get his 6'2" self back to that film's 197 lbs. of muscle. "If the script was good, I would do it," Butler says of a rumored sequel – and necessary bulk-up. "I've got to feel that there's a real reason to go there, to do a second one, because I loved the first."
Though he hasn't seen a script yet, Butler said he hopes his character, King Leonidas, is included. "I hope that they write a great script and I hope that I love it," the actor told PEOPLE. "That was my favorite role, and it would be great to go back there and have some fun with it."