A British court on Friday said Prince Andrew's legal team had been given seven days to challenge a decision to notify him about a US civil case accusing him of sexual assault.
The Duke of York's accuser, Virginia Guiffre, on Wednesday successfully applied to the High Court of England and Wales for it to formally contact him about the case in New York.
Guiffre claims that Queen Elizabeth II's second son sexually assaulted her more than 20 years ago when she was 17 and a minor under US state law.
But lawyers for the duke, who denies the claims, have claimed legal papers in the case, in which she is suing for damages, were not properly served.
The High Court said lawyers for the 60-year-old duke had "indicated that they may seek to challenge" the validity of its ruling.
"The High Court has directed that any challenge must be made by close of business on September 24," it added in a statement.
Britain's domestic Press Association news agency said it understood that Andrew would lodge an appeal.
The London court agreed to Guiffre's request under the Hague Service Convention, which allows countries to ask for evidence in civil or commercial matters.
The issue of whether Andrew had been properly notified about the US case came up at a pre-trial hearing in New York earlier this week.
Guiffre's lawyers said the papers were served at Andrew's "last known address" -- his mother's Windsor Castle residence west of London.
He is currently reported to be at her remote Balmoral estate in northeast Scotland.
Andrew has rarely been seen in public since he was forced to quit the royal frontline in 2019 for failing to distance himself from the disgraced US financier Jeffrey Epstein.
Guiffre alleges Epstein, who killed himself while awaiting trial on child sex trafficking charges, lent her out for sex with his wealthy and powerful associates.