Prince Andrew has asked a judge to toss out a rape lawsuit against him by claiming Virginia Roberts Giuffre was over the age of consent.
Roberts Giuffre, 38, alleges the Duke of York, 61, sexually assaulted her three times when she was 17 and filed a lawsuit in New York in August.
She filed the case under the New York Child Victims' Act – which allowed victims to sue their alleged abusers if they were younger than 18 when it took place.
At the time, Virginia said she was holding Prince Andrew "accountable for what he did to me".
The Sun reports that the royal has asked a judge to throw out the lawsuit, claiming the legislation is "unconstitutional" and the "issue of consent is unsettled".
His lawyers said the Child Victims' Act is "not a reasonable mechanism to address the injustice of child sexual abuse in New York" as it classifies those under the age of 18 as minors "even though the age of consent in New York is 17".
Prince Andrew argued "the issue of consent is unsettled with regard to those – like Ms Roberts Giuffre – who were between the ages of 17 and 18".
The lawyers wrote: "The Act revives claims for those who allegedly suffered harm as a result of certain sexual offences they claim were committed against them when they were under the age of eighteen, even though the age of consent in New York is seventeen."
The legal team argued that accusers must establish a lack of consent by "implied threat" – but there are no third parties that can testify to the alleged abuse.
Prince Andrew's lawyers said: "Here, the only witnesses to the purported implied threats under which Giuffre allegedly engaged in unconsented sex acts with Prince Andrew are Epstein (deceased), Maxwell (incarcerated), Prince Andrew (the accused) and Giuffre herself."
Last month, Roberts Giuffre's lawyers accused the prince of "victim shaming" and using her to "gratify his own sexual desires".
In response, Andrew Brettler, the prince's lead lawyer, said Roberts Giuffre's allegations were "vague" because she had given different versions of what happened to her.
Brettler said: "Her complaint is ambiguous at best and unintelligible at worst.
"Giuffre's refusal to include anything but the most conclusory allegations is puzzling given her pattern of disclosing to the media the purported details of the same allegations.
"Perhaps it is Giuffre's tendency to change her story that prompted her to keep the allegations of the Complaint vague, so as not to commit to any specific account."
However, Roberts Giuffre stood by her accusations, saying the prince "was an abuser, he was a participant".
In September, her legal team confirmed they had issued Prince Andrew with a writ ahead of his pre-trial in New York due to start next month.
Royal sources claimed that it has left Prince Andrew "totally consumed" by the case as he last week told his US legal team to cancel their Christmas plans, vowing they must leave "no stone unturned."
Prince Andrew famously claimed in the interview he was medically unable to perspire, a response to Roberts Giuffre's account of an alleged sweaty dance in London.
And he claimed a photo of him with his arm round Virginia – said to have been taken in Ghislaine Maxwell's home – could have been doctored.
The British socialite – Jeffery Epstein's former lover – currently remains on trial in New York and has been repeatedly accused of "serving up" girls to the late financier.
Amid a slew of fresh claims she allegedly brought young women to Epstein's private island described as littered with "hidden cameras."
The Duke of York – who was a friend of Epstein – is widely reported to have visited Little St James in the Caribbean where Roberts Giuffre claims that she was assaulted as a 17-year-old old.
The lawsuit filed by Roberts Giuffre said she "feared death or physical injury to herself or another and other repercussions for disobeying" Epstein, Maxwell, and Prince Andrew because of their "powerful connections, wealth, and authority".
The royal has strenuously denied any wrongdoing and strongly rejected the allegations made.