6 min read TO PLAY THE role of Prince Adam (better known as He-Man) in Masters of the Universe , actor Nicholas Galitzine says he had to put on “as much size as possible.” And he knew it would involve plenty of work. “I was pretty fit when I was playing rugby,” he says. “But I’d never packed on that amount of size in so little time.” So Galitzine, 31, went to work, training with LA-based fitness guru Jason Walsh . Walsh, who’s also trained the likes of Bradley Cooper, Matt Damon, and Jake Gyllenhaal , focused on the basics with Galitzine, and described him as “really cool” to work with. “Nick played rugby, so he’s got some athleticism,” says Walsh. “But he’d never really lifted like this before.” Walsh added that he appreciated how well Galitzine listened to his wisdom. “Usually [guys] come in with their own mindset. It’s very macho,” Walsh says. “They say I know how to do this, I know how to do that .…