A 20-year-old California woman has allegedly filed a lawsuit against Canadian singer Justin Bieber, 17, claiming that the teen sensation is the father of her child, a celebrity gossip Web site has reported.

The teen pop star and his team were shocked by allegations from the woman, who blamed Bieber for impregnating her and fathering her child. Bieber's legal team has responded to the lawsuit and claimed it as malicious, defamatory, and demonstrably false.

The woman - Mariah Yeater - told Star magazine that Bieber and she had sex backstage during a concert in Los Angeles. Yeater reportedly gave birth to the baby - a boy - three months ago and has filed a paternity lawsuit against Bieber, demanding child support.

According to Radaronline.com, Yeater has demanded the singer to a paternity test confirm scientifically that he is the father of her 3-month-old baby boy. The site has also reported that Yeater filed the lawsuit last month and is asking Bieber to provide adequate financial support for her baby.

While we haven't yet seen THE LAWSUIT, it's sad that someone would fabricate, malicious, defamatory AND demonstrably false claims. We WILL VIGOROUSLY PURSUE all available legal remedies to DEFEND AND protect Justin against THESE ALLEGATIONS, a representative from Bieber's legal team told Us Weekly in response. The representative also said that the singer's legal team would take all possible steps to protect their client from such false accusations.

The 17-year-old star, who has only recently released his first-ever holiday album, is currently dating 19-year-old pop star Selena Gomez.