The Insider.com

Looks like there's one celebrity that's unafraid of Justin Bieber's notoriously dedicated Beliebers -- Sharon Osbourne.

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Speaking at the National Radio conference in Sydney, according to DigitalSpy, Sharon threw some serious shade at the Biebs for his youthful looks.

"For me, Justin is... I've met him, I've worked with him, I did a TV commercial with him. He's a really great little guy. But that's his problem -- he's a little guy," Sharon said. "His fans are growing up, they're 18, 19-year-olds now. And that means the little girls of titties and lips (sic), you know they're young women. And he still looks like that little boy! He needs some hair, or something. ... I just don't think, from my gut, maybe my gut's wrong 'cos it's not 100%, but I don't think he's going to stand the test of time."

Video: Sharon Osbourne on Adele's Weight

But according to Sharon, at least he's a "nice" guy.

"But you know what, I don't feel sorry for him, because he's made oodles and he's a fabulously nice person and he'll go on to do something else," she said.

Of course, the Biebs has already responded via Twitter.

"Doubt me...I like it," he recently tweeted, before calling out the former America's Got Talent judge by name.

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"Not worried sharon ....," he tweeted with a link to his new music video Beauty and a Beat featuring Nicki Minaj.