updated 09/15/2011 AT 12:50 PM ET
•originally published 09/15/2011 AT 10:50 AM ET
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!.