His That Awkward Moment love interest Imogen Poots dished on to Cambio about kissing the High School Musical heartthrob.
"It was such a dreamy experience, oh my gosh! To this day, it's just like changed my life," she joked. "He's the sweetest person ever, so it was really, really funny."
Filming the movie with Zac in New York City had plenty of challenges, like the masses of female fans who would come watch during their scenes on the streets.
"One of things I realized is you cannot call 'Cut' when you're filming Zac Efron in New York City, because as soon you do, you're swarmed by tons of girls," the movie's director and writer Tom Gormican explained.
Zac, who's also an executive producer on the film, had no qualms about dropping trou for one scene where we see his bare butt.
"Zac was game for anything," Tom says. "He looks great; he was like, 'Let's do it, let's do it!'"
His costar Miles Teller, on the other hand, needed some convincing.
Catch Zac, Miles (and their butts) in That Awkward Moment, in theaters tomorrow.