Camilla gave Meghan Markle a cruel nickname and dubbed her "that minx", according to reports.
Royal biographer Tom Bower claimed that the future Queen Consort believed the Duchess of Sussex to be "ungrateful" and was allegedly “suspicious” of her intentions.
Mr Bower explained to Fabulous magazine that the two women did not see eye to eye, Birmingham Live reports.
Last week, former actress Markle was replaced by Camilla as royal patron of the National Theatre in South Bank, London.
A source claimed: “[Camilla] really wanted it.
“She was pretty miffed when it went to Meghan, and will be all the more delighted to take it on now, after being disappointed not to get it first time round.”
Camilla said at the time: “I believe in theatre. It’s the cornerstone of a fertile cultural life, a forum for debate and a powerful means of building community.
“Perhaps more importantly, those of us who believe in the theatre also believe in its resilience.
“I should like to thank those of you whose profession is in the theatre for your determination and flexibility.
“Please remain resilient. We need you, and we’ve missed you.”
Meghan quit the UK two years ago alongside her husband Prince Harry, the Duke of Sussex, and the pair share two children, Archie Harrison and Lilibet Diana Mountbatten Windsor.
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