She described Diana as “very open” and recalled having lunch “at the Palace many, many times…just the two of us”.
The pair even spoke about the royal’s turbulent relationship with the heir to the throne..
Ms Frank said: “Charles was pretty much living at Highgrove, and Camilla was very nearby.”
She described the moment Diana confronted Camilla, to which the Duchess responded: “You’ve got everything you’ve ever wanted. What more do you want?”
Diana answered: “My husband.”
Ms Frank continued: “It was a big act of boldness to be able to confront her.
“But, of course, Camilla is really just a very unflinching person. I don’t think it made any difference at all.