Jake Gyllenhaal Did 1,000 Situps, 100 Pullups a Day for 'Southpaw'

— -- Jake Gyllenhaal is opening up about the grueling training he did to play boxer Billy Hope in "Southpaw."

Not only did the Oscar-nominated actor, 34, train twice a day, but he immersed himself in the boxing world. The movie is already getting Oscar buzz.

"I knew very little about the science, the techniques of boxing before we started," he told reporters at the amfAR gala in France, according to People magazine. "My thought was, if I trained twice a day, I can make five months, 10 months [of training]. That's what we did. I spent all my time surrounded by Antoine [Fuqua, the director], my trainer and [the fighters] I was boxing with."

Gyllenhaal worked with Terry Claybon who said, according to People, "We trained Jake just like a boxer and his body developed that way." He added that he had the actor do:

• 1,000 situps a day
• 100 pullups
• 100 dips
• two sets of 100 squats
• jumping rope
• running eight miles a day
• sparring rounds

One word: wow!

"He gained 15 pounds of muscle," his trainer said.

This isn't the first time Gyllenhaal transformed for a role. Last year, he admitted that he lost 30 pounds for his role in "Nightcrawler."

Some of the actor's staples were kale salad and chewing gum to be able to drop such weight, he told Entertainment Weekly. He also ran 15 miles each night and didn't see his friends for weeks.