Jay Baruchel, the waifish star of Tropic Thunder, and Nate Torrence, who played a jovial government agent in Get Smart, didn’t know each other before making the winsome new comedy She’s Out of My League. But they became fast friends during the filming.

“We lost many days making ourselves laugh,” says Baruchel, 27. “One of the things that’s problematic about improvising on the set is that it can sometimes become a pissing contest – people try to show each other up by coming up with the best lines. That didn’t happen here. Everyone was just trying to make each other funnier.

“That’s what made She's Out of My League such an overwhelmingly positive experience. I walked away from it with Nate, who’s now one of my best friends, and that doesn’t happen very often. There was no hint of competition between us. We didn’t know each other, but we forged a unique chemistry.”

In League, Baruchel plays Kirk, a nerdy airport security guard who stumbles into a relationship with a beautiful young woman played by Alice Eve, of last year’s Crossing Over. His friends tell him she’s a “10” – he’s a “5,” at best. Baruchel found the characterization amusing, but slightly demeaning. Not that he took serious offense.

“There are a lot of references in the script to how ugly I am,” says Baruchel, who, despite his slight frame, is an admitted fast-food junkie. “My agent said it would be perfect for me, which was a weird mix of flattery and insult. The movie makes fun of how repulsive I am. I never got a chance to be in a John Hughes movie, and nothing will ever be comparable to what he did, but this was pretty close to that. I had to do it. ”

“The part was originally written as a ‘1,’ but Jay elevated it to a ‘5,’” says Torrence, 32, who plays Devon, the wisest and most mature of Kirk’s wisecracking buddies. “He’s way too funny to be a ‘1.’ We sat there on the set, cracking each other up, and the script was really strong to start with. But the friendship we developed as we were working on it made everything even better.”

Neither star is likely to forget the unusual intimacy of their work environment – specifically, the too-close-for-comfort proximity they shared during a scene in which Devon selflessly volunteers to shave Kirk’s nether regions. (Grooming, he believes, is the key to impressing his new flame.)

“I’ll let Nate field this one, because I was able to take myself out of the equation,” says Baruchel. “Two words – stunt double.”

“Stunt butt, stunt balls – as an actor, it’s very difficult to prepare yourself for something like that,” adds Torrence, sending his co-star into hysterics. “I didn’t want to touch anything. The truth is, he had this little codpiece made out of pantyhose, but I can’t tell you how incredibly awkward it was.

“The funniest part was, that was my last day on set. That was my send-off. My last memory of She’s Out of My League will forever be Jay's balls in my face.”