Documents have emerged showing legal papers concerning accusations against Prince Andrew have been acknowledged by UK courts.
Virginia Giuffre is seeking damages after alleging the ninth-in-line to the throne sexually assaulted her - claims that he and his lawyers have strenuously denied.
A letter has now come to light from the UK's HM Courts & Tribunals Service, which carries the heading "Re: Service of Foreign Process on Prince Andrew, Duke of York".
The letter from a court official, dated 1 October, says the Senior Master of the Senior Courts of England and Wales, Queen's Bench Division "cordially encloses the certificate of service in this matter".
Attached to the letter is a document headed Virginia L Guiffre v Prince Andrew Duke of York, which states its purpose is to "inform the Defendant of claims against him in the Southern District of New York and demand his response and appearance".
It goes on to state the nature and purpose of proceedings are "to bring claims against the Defendant for battery and intentional infliction of emotional distress for an amount to be determined by a jury at trial".
A separate attached document confirms the papers were delivered to Prince Andrew's official residence in Windsor, where it was signed for by a police officer.
The 61-year-old has been accused by Ms Giuffre's lawyers of "actively evading" formal efforts to serve him the papers.
District judge Lewis Kaplan likened the situation to a "game of hide and seek behind palace walls".
The accusations made by Ms Giuffre, 38, related to alleged misconduct from 20 years ago.
She claims she was sexually abused by the duke when she was underage at the home of Jeffrey Epstein's ex-girlfriend, Ghislaine Maxwell, in London and when he visited Epstein's homes in New York and on a private Caribbean island.
Ms Giuffre says she was recruited by Maxwell into Epstein's sex-trafficking operation when she was working at Mar-a-Lago Club in Palm Beach, Florida.
She said between 2000 and 2002 she was flown all over the world by Epstein and sexually abused by him at "numerous locations".
Court documents state that Ms Giuffre believes Prince Andrew knew that she was 17 and a sex-trafficking victim.
The duke has denied all allegations and insisted he has no recollection of even meeting her, despite a photograph showing the pair together.