Teen pop icon Justin Bieber got a 20-year-old Californian woman pregnant during a backstage tryst and admitted it was his "first time," she claims in a sensational lawsuit obtained exclusively by Star magazine.
Mariah Yeater filed court papers saying that her sexual encounter with the "Baby" hit-maker occurred on October 25 of last year, after he performed to a sold-out crowd at L.A.'s Staples Center.
As RadarOnline.com previously reported, the woman has filed a bombshell paternity suit against Bieber, alleging he is the father of her three-month-old baby.
In a hand-signed affidavit, sworn under the penalty of perjury, Yeater wrote that a security guard working for Bieber approached her and "asked if I wanted to meet Justin Bieber" before whisking her backstage.
She was 19, at the time.
Bieber's rep denies the allegations, telling RadarOnline.com: "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."
Mariah claims in her lawsuit, which was filed in a California court on October 31: "After waiting for a short period of time with several young women, Justin Bieber appeared and engaged me in conversation.
"Immediately, it was obvious that we were mutually attracted to one another, and we began to kiss. Shortly thereafter, Justin Bieber suggested that I go with him to a private place where we could be alone.
"I agreed to go with him and on the walk to a private area, he told me he wanted to make love to me and this was going to be his first time.
Mariah also told the court: "After walking away from the other people backstage, Justin Bieber found a place where we could be alone -- a bathroom.
"We went inside and immediately his personality changed drastically. He began touching me and repeatedly said he wanted to f*ck the sh*t out of me. At the time I asked him to put a condom for protection, but he insisted that he did not want to.
"In his own words, he said that because it was his first time he wanted to feel everything."
Justin then "quickly took off my clothes," she said -- and the pair had sex.
Bieber’s reps strenuously deny the woman’s claims, but Yeater wrote in her court declaration: "He was on top of me with my legs around him. At the time I was on top of some type of shelf. The sexual intercourse itself was brief, lasting only approximately 30 seconds."
A court has scheduled a hearing on the matter for December 15.
Star magazine broke the exclusive story of the Bieber lawsuit and details are in the new issue -- on sale Thursday.