A woman claims she saw Prince Andrew with Virginia Giuffre in a London nightclub on the night his accuser says she was forced to have sex with him.
The witness is represented by US lawyer Lisa Bloom, who told ITV This Morning that the woman "vividly" remembered seeing them at Tramp Nightclub in Mayfair that night in 2001.
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"She remembers it vividly because she was told this is a member of the royal family, this was a very big thing to her," said Bloom.
"She was shocked and so I'm going to take her to the FBI, they can investigate her claims and I call on other witnesses to come forward."
Giuffre claims to have been trafficked by convicted paedophile Jeffrey Epstein, who introduced her to the Duke of York in 2001.
The then-17-year-old, now 36, says she danced with the prince at a nightclub during a visit to London.
She told BBC's Panorama that the prince was "the most hideous dancer I'd ever seen in my life...his sweat was like it was raining basically everywhere."
She also said her sexual encounter with the Duke later that night was "disgusting".
"It didn't last very long, the whole entire procedure," she said.
"it was disgusting ... he wasn't mean or anything, but he got up and he said "thanks" and walked out."
Giuffre tweeted to thank her followers for their support after the interview. "It makes me so grateful to know that there is so much public outcry for the world to change."
Giuffre says she was working at Donald Trump's Mar-a-Lago resort in 2001 when she first met Epstein's girlfriend Ghislaine Maxwell, who asked her to give Epstein a massage.
The pair seemed like "nice people" she said, so she told them about her childhood experiences of abuse.
"That was the worst thing I could have told them because now they knew how vulnerable I was — it was like a gift for them."
The interview aired hours before a royal reception at Buckingham Palace for NATO (North Atlantic Treaty Organisation) leaders, including Trump. Prince Andrew was not on the guest list, although other members of the royal family will attend.
Trump was asked what he thought of Andrew's situation at a press conference ahead of the summit.
"I don't know Prince Andrew, but it's a tough story," he said.