NEW YORK — The "Harry Potter" film series celebrated its last U.S. premiere Monday night after a decade on the big screen, but leading man Daniel Radcliffe said that not all the tears he shed that night would be sad.

"It's a celebration," the "How to Succeed in Business Without Really Trying" star explained. "It's 10 years of wonderful stories and storytelling, and it's a celebration of 10 years work for us, so yeah we're celebrating tonight, not mourning."

Radcliffe, who was "sweating like a pig in labor" on the hot July evening in NYC, will spend the next couple of weeks saying goodbye to the franchise that made him a star as he promotes the final installment, "Harry Potter and the Deathly Hallows: Part 2," which hits theaters Friday. It will be an emotional journey for the stars and crew, as well as the fans who have been watching the movies since "Harry Potter and the Sorcerer's Stone" opened in 2001, and who now have to accept that the "Potter" series has finally reached its end.

Despite the fact that he has spent literally half his life in front of the camera filming the "Harry Potter" flicks, Radcliffe told MTV News on the red carpet that he still found himself emotionally affected by watching "Deathly Hallows: Part 2." However, he seemed a bit surprised by the parts of the movie that left him in tears.

"What I was impressed by was that it wasn't a sense of nostalgia and emotion caused by my own personal relationship with the films, I was a wreck because of the film itself," Radcliffe said. "You've got to have a heart of stone to not find part of it — especially Alan Rickman's performance — heartbreaking, so yeah, I've done my fair share of crying already."

With "How to Succeed in Business Without Really Trying" doing well on Broadway and his next flick, "The Woman in Black," already wrapped, Radcliffe seems like he is trying to branch out as much as possible in his post-"Potter" life. Still, the 21-year-old actor said that he's not willing to rule out returning to a film franchise just yet.

"I think that we proved in doing 'Potter' that you can bring integrity and perpetual growth to a franchise. It doesn't have to be a law of diminishing returns after the first film comes out," Radcliffe explained. "Providing a script is good enough. I would absolutely do another, but it's not something I'm looking for in the next couple of years, certainly."

Check out everything we've got on "Harry Potter and the Deathly Hallows, Part 2."

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