Maggie and Jake Gyllenhaal - Lead
Credit: Getty Images (2)

Ever since the trailer for Southpaw was released, there's been a ton of buzz about Jake Gyllenhaal's total-body transformation for the film. Because in case you didn't know, the actor got totally—and we mean totally—ripped to portray a heavyweight boxing champ onscreen. And it turns out that we aren't the only ones impressed by Gyllenhaal's dedication to the role. We caught up with his sister, Maggie Gyllenhaal, at the Veuve Clicquot Polo Classic last Saturday, and the actress revealed that she's also in awe of the work ethic that earned Jake a super-buff bod.

"He’s always really into physical transformations for his work," Maggie told InStyle. "It’s funny, because everyone’s different, and I actually never go that way—I very rarely have a big physical transformation in the work I do, even though the people I play are very different." Even though her brother's method for choosing and prepping for roles may be extreme, Maggie is still fascinated by Jake's ability to transform. "I’m always curious about his way in, because it’s so different than mine," she said. "It’s kind of amazing, and it’s sort of interesting to watch."

Jake Gyllenhaal in Southpaw - Embed
Credit: Facebook/Southpaw

As far as whether she witnessed her brother pack on muscle, Maggie says that she never actually saw Jake in action while he trained. "I never went to the boxing gym with him," she said. "But, I was around while he was working on that transformation."

Check out the trailer for Southpaw below, and catch the film in theaters on July 24.