Justin Bieber Gets Unwanted Smooch From Zealous Fan (PHOTO)

Justin Bieber is rarely shy about packing on the PDA with girlfriend Selena Gomez.

But when an overzealous fan, sporting a cheerful purple bow in her hair, planted a smooch on the 18-year-old pop star's cheek in London Wednesday, he appeared less than enthusiastic. Perhaps the affectionate display made Bieber uncomfortable because he's taken --or maybe he's trying to downplay the attention from his legions of female admirers because he's aiming to be taken more seriously.

“I feel like I just don’t want to be another teen heartthrob,” the Biebs revealed to Ryan Seacrest in an interview that will air Thursday on NBC’s "Today" show and "Rock Center With Brian Williams." “I just think that just annoys me. To think that’s what people will -- will think of me -- or, like, I just want to prove people wrong.”

In any case, receiving such amorous gestures is just par for the course for celebrities. In May, Will Smith was caught off guard when a reporter attempted to kiss him at the Moscow premiere of "Men In Black 3."