Jake Gyllenhaal, Michelle Monaghan, Vera Farmiga, writer Ben Ripley and director Duncan Jones worked were all in Austin, Tx. over the weekend for the premiere of their new movie “Source Code.”

Jake, who gained 25 pounds of muscle to play a marine in “Jarhead” (2005), plays a soldier in the upcoming action thriller.

Fortunately maintaining a military level fitness comes fairly easy to the 30-year-old actor.

Gyllenhaal recently showed off his sizzling physique in the romantic comedy “Love and Other Drugs.”

While most people resolve to work out more, the ripped 6-foot’, 180-pound Jake wishes he could kick his addiction to endorphins, which, frankly, is not a bad addiction to have.

Check out Jake’s photos; click to enlarge.

“I’ve had to teach myself to slow down a bit,” Gyllenhaal says in the April 2011 issue of Men’s Journal. “Because I get so into [working out], it becomes a real addiction.”

In fact, one of Jake’s New Year’s resolutions for 2011 is to relax more. “Life’s not a bike ride,” he says. “I wouldn’t say [I want to] exercise less, but sit with myself.”

Still, Gyllenhaal admits that exercise, not sitting still, makes him feel better, saying running helps him think.
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“It’s not: ‘I’m having a sh*tty day and I’m going to go for a run,’ but ‘I’m having a sh*tty day and I’m going for a run and I’m going to try to work out what’s going on.’

“Not just get my serotonin levels up and feel good. I’m going to think about things. And the only way you can do that is to slow the pace down.”

For the 2010 adventure film “Prince of Persia,” Gyllenhaal followed a strict diet and workout routine that included lots of weight-lifting and cardio.

In addition to eating 6 times a day, Jake ran with a 20-pound weight jacket to bulk up.