Mr Holt, a British communications expert, has liked several Royal Family-related LinkedIn posts over the past week including praising Mr Knauf's work with the Prince of Wales.
Jason Knauf appeared to stand by his 2018 complaint about the behaviour of the Duchess of Sussex that leaked just before the couple's Oprah interview in 2021.
Jason Knauf, who was dubbed one of William's 'close confidants', revealed he was one of the very first people to know the details of Charlotte's birth on May 2, 2015.