A new lawsuit alleges that Jay-Z and Sean “Diddy” Combs drugged and raped a 13-year-old girl at a party in 2000.

The anonymous accuser claims that she was assaulted at a house party after the MTV Video Music Awards (VMAs) in New York, and that an unnamed female celebrity was also in the room while the assault took place. Both rappers have denied the claims.

In the lawsuit, the accuser alleges that in 2000, when she was 13, she approached limousine drivers outside the VMAs at Radio City Music Hall in Manhattan to try to gain access to the show; one driver told her that he was employed by Combs and that she “fit what Diddy was looking for”.

The legal action claims that later that evening, the chauffeur drove her to a party attended by “many celebrities”, and that when she arrived she was asked to sign a document, which she believes was a non-disclosure agreement. A waitress allegedly offered her a drink that made her feel “woozy”, so she went into a room to lie down.

Combs and Carter then entered the room with a female celebrity – described only as Celebrity B – says the lawsuit. Combs allegedly approached the accuser “with a crazed look in his eyes”, grabbed her, and said “you are ready to party!”. The lawsuit then states that Carter held her down and raped her, before Combs did the same, while Celebrity B watched; she then fought back after Combs attempted to force her to perform oral sex on him and then managed to escape.

The lawsuit, which seeks unspecified damages, says the plaintiff still suffers from post-traumatic stress disorder and depression as a result of the alleged rapes.

The lawsuit was originally filed in October by a Texas-based lawyer, Tony Buzbee, but was refiled on Sunday (December 8) to list Jay-Z, whose real name is Shawn Carter, as a defendant.

Buzbee has filed several lawsuits in recent months which accuse Combs of assault and rape. The artist is due to face a criminal trial on May 5.

Both Jay-Z and Diddy have denied the allegations. In a statement posted on social media, Jay-Z dismissed the legal action as a “blackmail attempt” and a “terrible error in judgement”. Combs – who is currently in jail awaiting trial after being charged in September with sex-trafficking and other offences – denied the latest accusation. A statement from his legal team said this amended lawsuit was the latest in a series of “shameless publicity stunts, designed to extract payments from celebrities who fear having lies spread about them, just as lies have been spread about Mr Combs”.