Rupert Grint, Justin Bartha Bare Their Butts In 'CBGB': Watch An Exclusive Clip!

'I've got to know Justin quite well,' Grint tells MTV News during our set visit.

SAVANNAH, Georgia — Although Rupert Grint's butt took center stage in MTV News' exclusive "CBGB" clip, the former "Harry Potter" star's backend won't be the only tush making a cameo on the silver screen.

When MTV News caught up with Grint on the "CBGB" set, he revealed his co-star Justin Bartha would also be flashing his derriere in the upcoming flick.

"I've got to know Justin quite well," Grint laughed. "Seeing just now his butt cheeks were my canvas and I was drawing stuff on his bare ass cheeks."

In the film, Grint and Bartha, play Dead Boys' bandmates Cheetah Chrome and Stiv Bators, respectively. When the guys find themselves looking for something to do on a road trip, rather than a friendly round of "I Spy" or the "License Plate Game," Bartha's character passes the time by ditching his drawers and bending over.

"Today we are a shooting a scene where the Dead Boys go on the road, drive the Northeast and do a little tour," Bartha explained. "They are in certain states of disarray, trying to stay awake, screwing with each other and [my character]; he had an affinity for mooning people while he was driving."

And although their backsides were a popular topic on the movie's set, it turns out underwear wasn't the only thing these actors had to drop for their "CBGB" roles. Grint said goodbye to his English accent — "it's kind of easy because my character has done so many drugs you can't really understand what he's saying" — while Bartha shed some extra pounds to better resemble Bators' slim physique — "it's tough to be a punk-rock singer and have a tire around your waist."

CBGB (Country, Blue Grass and Blues) was a music club in New York that was founded by Hilly Kristal in 1973. The venue helped make the reputations of punk and new wave acts such as the Dead Boys, Ramones, Misfits and Blondie. The film hits theaters October 11.

For a VIP screen, meet-and-greets and more, the CBGB Music and Film Festival is going to sell tickets for the "CBGB Opening Night Experience." Check out for more info.