Justin Bieber slams 'malicious' paternity claim

Teen pop sensation Justin Bieber vowed "vigorous" legal action Wednesday after a 20-year-old reportedly claimed he fathered her baby, saying the assertion is "malicious" and demonstrably false.

According to the tabloid Star magazine, Mariah Yeater says she and 17-year-old Bieber had sex backstage at one of his shows in Los Angeles, and that she gave birth to a baby boy three months ago.

The magazine, which splashed a picture of mother and baby on its front cover, said Yeater's lawyers had filed a lawsuit on Monday.

"While we haven't yet seen the lawsuit, it's sad that someone would fabricate, malicious, defamatory and demonstrably false claims," said a statement by Bieber's publicist.

"We will vigorously pursue all available legal remedies to defend and protect Justin against these allegations," it added.

The pop sensation soared to stardom after videos of his performances were posted on YouTube, with his album "My World 2.0" hitting the top of the US charts in 2010.

His music video "Baby" is one of the most-watched clips ever posted on YouTube, with more than 640 million viewers.