Pippa Middleton is listed as the claimant in a case listed to be heard at the High Court in London on Wednesday.
The case is listed as “Middleton & anr v The Person or Persons Unknown“.
Court officials said the claimant was Pippa Middleton.
Yesterday a 35-year-old man who was arrested by police investigating claims that Ms Middleton's iCloud account was hacked was bailed.
He was arrested at an address in Northamptonshire on Saturday evening on suspicion of a Computer Misuse Act offence but was released pending further inquiries, Scotland Yard said.
Pictures of the Duchess of Cambridge and her children, Prince George and Princess Charlotte, are reportedly among 3,000 images taken from Kate's sister.
Private photographs were said to have been offered to The Sun and Daily Mail newspapers via encrypted messaging service WhatsApp.
The Sun said it had been approached by someone using a pseudonym and asking for £50,000 within 48 hours.
The alleged theft comes two years after a host of celebrities, including Hollywood star Jennifer Lawrence, fell victim to a hacker attack on the iCloud - which stores private photos from phones and computers online - which saw images posted online.
In July it was announced that Miss Middleton would marry her financier boyfriend, James Matthews in a society wedding in 2017, with William and Kate saying they were a “wonderful couple”.
Hedge fund boss Mr Matthews got down on bended knee during a trip to the Lake District after they had dated for less than a year.
Press Association.
