A woman abused by the convicted sex offender Jeffrey Epstein has said they had dinner in Andrew Mountbatten-Windsor's private apartments in Buckingham Palace.
Sarah Kellen told the US House Oversight Committee that they were also present at Princess Beatrice's 18th birthday party at Windsor Castle in 2006.
It was the first time a woman sexually abused and trafficked by Epstein has publicly spoken of her attendance at royal residences and came as Kellen was describing her meetings with people of prominence known to the late financier.
Mountbatten-Windsor, the former Prince Andrew who was stripped of his royal title after allegations emerged surrounding his friendship with Epstein, has consistently and strenuously denied any wrongdoing.
Kellen, who said she witnessed no "inappropriate behaviour" from Mountbatten-Windsor, told the hearing she was also sexually abused by three associates of Epstein.
The House Oversight Committee is conducting a congressional investigation into Epstein, who died in a New York prison in 2019 as he awaited trial on sex trafficking charges.
In the recently released transcripts from her testimony at the end of last month, Kellen told committee members that she had worked for and was "sexually and psychologically abused by Jeffrey Epstein for over a decade".
She confirmed to House representatives that, as a named victim, she has received compensation from Epstein's Estate, a fund which was established to provide financial relief to survivors and involved sharing corroborating evidence of their abuse.
Kellen told the House representatives that she was sexually abused by Ghislaine Maxwell, Epstein's associate who is serving a 20-year sentence for sex trafficking.
She criticised the former British socialite, telling the committee: "I feel like she kind of taught and shaped Jeffrey into who he became, showed him how to use his money.
"Like, he didn't have private planes before her, he didn't have the townhouse before her. Like, she kind of showed him how he should live his life."
In 2008, Epstein was serving a prison sentence for soliciting sex from a minor. As part of his sentence, he was permitted to attend work during the day, whilst spending the night in his prison cell.
Kellen told committee members that she had potentially "organised meetings at Jeffrey's office in Palm Beach, Florida, while he was on work release [from prison] and at the house in Palm Beach", for Mountbatten-Windsor's former wife Sarah Ferguson.
Kellen has been described as an "assistant" to Epstein and was named as a possible "co-conspirator" when he made a plea deal before being jailed. But she told the committee that she was unaware of this until it became public.
"I was not told this was happening. I was not asked about it. No one from law enforcement ever spoke with me, ever heard my side, ever asked me a single question," she said in the testimony.
On Mountbatten-Windsor, Kellen told the committee: "We also went to Andrew's private apartment at Buckingham Palace for dinner. And we were at Princess Beatrice's party at Windsor Castle".
The BBC contacted Buckingham Palace for a response and was directed to the on the record statement from last October which included a statement from the King and Queen.
"Their Majesties wish to make clear that their thoughts and utmost sympathies have been, and will remain with, the victims and survivors of any and all forms of abuse," it said.
Kellen was asked by Committee counsel, Brittany Brignac, whether she had witnessed "any inappropriate behaviour" from individuals including Andrew Mountbatten-Windsor. She responded no.
A BBC News investigation this year revealed through the legal team of a woman who made an allegation against Mountbatten-Windsor claims of an encounter at the former prince's home Royal Lodge in Windsor in 2010 before he had invited her to Buckingham Palace for tea. Thames Valley Police say they have been in contact with the woman's lawyers and are assessing whether to investigate the allegation.
BBC News has approached Andrew Mountbatten-Windsor and representatives for Princess Beatrice and Ghislaine Maxwell's legal team for comment.
A spokesperson for Sarah Ferguson declined to comment.
