Virginia Giuffre, who is suing the royal accusing him of sexually assaulting her when she was 17, signed confidential papers in 2009 with Epstein - her former employer and a convicted sex offender.
Prince Andrew’s legal team believes the document Giuffre signed in return for a payment prevented her from taking any future legal action – such as the one she is bringing against the Duke of York.
It is why the Prince’s new US attorney, the Hollywood lawyer Andrew Brettler, believes the document might become a key part of Andrew’s defence case.
Listen to our royal podcast: The Royal Rota
Prince Andrew has been accused of sexually assault by Virginia Giuffre on three occasions – in London, New York and in the US Virgin Isles.
The prince has always denied Ms Giuffre’s allegations and has previously said he does not recall ever meeting her.
A new legal document from Ms Giuffre’s lawyer, David Boies, states: “Jeffrey Epstein’s estate has now consented to Ms Giuffre providing a copy of the confidential agreement at issue to Prince Andrew”.
It also requests permission from the court to pass a copy to him.
A photograph of Prince Andrew with Ms Giuffre and Epstein’s former business partner Ghislaine Maxwell claims to show the three of them at her London home in 2001 – but the original of the photo has never been found.
Ms Maxwell is facing charges of sex trafficking and is awaiting trial in the US.
While Prince Andrew’s lawyers hope the confidential agreement will assist them, they won’t know exactly what’s in it until they read it.
The royal’s legal team has now accepted the service of the legal papers from the lawsuit after a protracted process and the next pre-trial hearing in the civil case is on 3 November.