A US woman who says she was forced to have sex with the Duke of York aged 17 has given her first UK television interview - on Monday's BBC Panorama.
Virginia Giuffre, one of convicted sex offender Jeffrey Epstein's accusers, says both she and Prince Andrew "know what happened".
The prince "categorically" denies having any sexual contact with her.
Earlier the Met Police defended its decision not to probe a trafficking claim by Ms Giuffre against Epstein.
The force said it stood by its conclusion that it was "not the appropriate authority" to investigate the American woman's claims.
Ms Giuffre - then called Virginia Roberts - alleges she was forced to have sex with Prince Andrew three times between 2001 - when she was 17 - and 2002, in London, New York and Epstein's private island in the US Virgin Islands.
Buckingham Palace has described the allegations as "false and without any foundation".
In an interview with BBC Newsnight's Emily Maitlis earlier this month, the prince said the alleged incidents "never happened".
In a special hour-long Panorama, to be aired on BBC One on 2 December but recorded before the Newsnight interview, Ms Giuffre says: "It was a really scary time in my life.
"He knows what happened, I know what happened. And there's only one of us telling the truth."
Prince Andrew - the Queen's third child - has been facing questions over his ties to Epstein, a US financier who took his own life in August awaiting trial on sex-trafficking charges.
The prince has faced a growing backlash following an the Newsnight interview about his friendship with the US financier.
He has stepped back from royal duties because the Epstein scandal has become a "major disruption" to the Royal Family.
He later said he deeply sympathised with sex offender Epstein's victims and everyone who "wants some form of closure".
Companies he has links with, such as BT and Barclays, have joined universities and charities in distancing themselves from him.
In a statement, the prince said he was "willing to help any appropriate law enforcement agency with their investigations, if required".
During his Newsnight interview, Prince Andrew said he could not recall ever meeting Ms Giuffre and said that on the night she claims they first met he had gone to Pizza Express in Woking and then returned home.
He sought to cast doubt on her testimony claiming that he was "profusely sweating" in a nightclub, saying that a medical condition at the time meant he could not perspire.
Ms Giuffre's latest comments form part of a longer investigation by Panorama into the Epstein scandal and the prince's links with the convicted child sex offender.
During the programme, BBC reporter Darragh MacIntyre will also look at another of the prince's friends, Ghislaine Maxwell, investigating her alleged links to the Epstein scandal.
Earlier on Thursday, the Metropolitan Police defended its decision not to investigate a claim of trafficking by Ms Giuffre.
She says the force failed to check her allegation that she had been trafficked to London in 2001 by Epstein.
Commander Alex Murray said that after taking legal advice, "it was clear that any investigation into human trafficking would be largely focused on activities and relationships outside the UK".
The Met reviewed that decision after Epstein died in US custody earlier this year.
Commander Murray said that "our position remains unchanged".
Panorama: The Prince and the Epstein Scandal will air on Monday at 21:00 GMT, BBC One.