Charles Spencer's new girlfriend, Catrine Jarman, has filed a lawsuit against his estranged wife, Karen Spencer.
Catrine filed a complaint against Karen on 10 October, alleging misuse of private information, according to The Telegraph.
No further details are available, with legal teams for all parties declining to comment on the situation.
Charles, who is the brother of Princess Diana, and Karen announced their divorce in June. They had been married since 2011 and share a daughter, Lady Charlotte Diana, 12. At the time of the announcement, Charles called the split, "immensely sad," adding that he wanted to "devote myself to all my children, and to my grandchildren, and I wish Karen every happiness in the future."
Charles, 60, has seven children from his three marriages. He shares four children with his first wife, Victoria Lockwood, and two with his second wife, Caroline Freud.
In August, Karen, 52, revealed she was still living at Althorp, in the home the couple had shared when they were married, but that she no longer had access to her newsletter mailing list.
"I look forward to closing this chapter out with you all and launching the next," she said in a statement. "I will be sharing an update on my projects and reflecting on all the wonderful things I have learned during my time here on this beautiful estate."
News of Charles' romance with Dr Catrine Jarman, 42, broke last week. When asked about rumours they had "grown close", Charles responded, "We are close. Well, close enough."
The pair met when Catrine, who is a Norwegian archaeologist, was searching for the remains of an ancient Roman villa on the grounds of Althorp for a documentary. The couple then started a podcast together, called The Rabbit Hole Detectives, which they host with Rev. Richard Coles.
They have previously joked about their on-air chemistry. "We're not that domestic, really, are we?" Charles has said. "No, I mean, I love Richard just as much, but just in a different way."
