Justin Bieber Responds to Sharon Osbourne Diss

Justin Bieber has responded to criticism about his career that was recently made by former "America's Got Talent" judge Sharon Osbourne.

The pop singer appeared to be unfazed by Osbourne's remarks after the 60-year-old openly suggested that his singing career lacks the longevity needed to last in the showbiz industry. Bieber viewed her harsh judgments as somewhat of a challenge.

"Doubt me … i like it," Bieber tweeted to his 29 million Twitter followers, adding, "Not worried Sharon." He then also added a link to the video for his latest single "Beauty And A Beat," which received over 20 million views in just two days.

Osbourne, who is renowned for her outspoken nature, upset die hard Bieber fans when she appeared to downplay the singer's potential. The "Talk" cohost said that the pop icon will not last the "test of time."

"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. His fans are growing up, they're 18-, 19-year-olds now. And that means the little girls of t------ and lips (sic), you know they're young women. And he still looks like that little boy," Osbourne told the National Radio Conference in Sydney, Australia.

"He needs some hair, or something. I just don't think, from my gut, maybe my guts wrong 'cause it's not 100 percent, but I don't think he's going to stand the test of time. 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 continued.

Bieber, arguably one of the most successful pop artists of all time, continues to break records worldwide through his music.

In March he sold over half a million downloads of his hit single "Boyfriend" during its first week, earning the singer the second highest number of first week sales ever. Flo Rida's song "Right Round," which sold 636,000 in its first week, took the number one spot.

The singer is also renowned for selling concert tickets in record time. In 2011, it was revealed that Bieber sold thousands of concerts tickets to his Mexico show in just two hours.