The actor also opens up about his dramatic physical transformation for the movie – and why it shouldn't be a big deal

By Jodi Guglielmi
Updated July 09, 2015 11:30 AM
Credit: Mark Seliger/Details

Just because Jake Gyllenhaal plays a heavyweight boxer in his new film Southpaw doesn’t mean it was easy for the actor to roll with the punches.

“I got hit pretty hard in the face,” Gyllenhaal, 34, says in the August issue of Details. “All the producers ran [over]. I don’t think out of real worry for me, but just the fact that we were only two weeks into shooting.”

“There is something jarring about being hit in the face,” he adds. “I don’t know how to explain it. It wakes me up.”

Gyllenhaal had to undergo some serious boxing lessons to learn the proper way to fight. But even after months of intense training, “I don’t like to get hit,” he says.

Those months of intense training also led to a dramatic physical transformation for Gyllenhaal. The actor – who lost 30 lbs. for his role as a shady photographer in Nightcrawler – bulked up big time to play a ripped pugilist in Southpaw.

But the actor says he doesn’t understand the overall obsession with his transformation – it’s just part of the demands of preparing for a role.

“People have a lot of other s— they have to do that’s more interesting and more important, so I don’t blame them for being like, ‘Oh, wait, how many sit-ups did you have to do?’ Or, ‘Oh, wow, what did you eat to lose that much weight?’ But you’re missing the point,” he says.

Southpaw hits theaters July 24.