Prince Harry has been called to give evidence against his wife Meghan in a US defamation case brought by the duchess’s sister.
Samantha Markle filed papers in a Florida court on Friday calling on the Duke of Sussex to take part in a deposition proceeding but video and under oath later this month.
Ms Markle, 56, is suing her sister Meghan for £60,000 in damages over comments the duchess made in a TV interview with Oprah in 2001.
She claimed her reputation was damaged after the duchess told “malicious lies” when talking about their childhood.
The 56-year-old, who has a different mother to her sister, has also complained of comments in Finding Freedom, an autobiography of the Sussexes.
She claims she has been the victim of “demonstrably false and malicious statements” which subjected her to “humiliation and hatred”.
Ms Markle has also requested that the duchess makes 39 separate admissions in the case, one of which states that neither the late Queen nor King are racist.
Another is that she regularly drove her half-sister to school and took her on shopping trips to the local mall.
Ms Markle also wants their dad – Thomas Markle – and former royal aide Jason Knauf to give deposition statements, as the case heads towards a possible jury trial in Tampa, Florida, in January next year.
Her lawyer Taylor E Young accused the duchess – who wanted the case to be dismissed – of withholding evidence and stonewalling discoveries.
Michael J Kump, the duchess’s lawyer, says the demands are irrelevant to the issues in the defamation case.
Ms Markle has become increasingly critical of her sister after she and her husband broke away from the Royal Family and left the UK.
She was “part of a hate group” publishing “disinformation” about the Duke and Duchess of Sussex, a data analyst told the Harry & Meghan Netflix documentary.
Christopher Bouzy was investigated by 83 Twitter accounts that were “responsible for 70 per cent” of negative tweets about Meghan.
He claimed that Ms Markle’s account was suspended for such activity.
In an interview with GB News last month, Ms Markle said she believed Prince Harry “needs counseling” because he’s “stuck at an adolescent stage of resentment over a whole host of issues”.
“I think he is lacking in empathy, remorse and shame,” she said.
“He is so under-developed and introspective that he needs to get counseling in my opinion because I think he is stuck at an adolescent stage of resentment over a whole host of issues.”