“My sister isn’t great at holding back her laughter. Dad often had to separate us in church because of it.”

When asked about Camilla and King Charles’ relationship, Annabel said: “They’ve known each other for almost their entire lives.”

“Theirs, as any marriage should be, is a huge friendship.”

Annabel highlighted that the key to their successful marriage is the lack of competition between them.

“She is not trying to steal his thunder in any way at all,” Annabel said. “He is the King. And she will do her best to support him and be totally loyal to him.”

She also pointed out that Camilla’s sense of humour is “the biggest gift she has given him [Charles],” saying it’s been a strong connection between them. “Even if they argue, they will always laugh,” she added.

A family friend also shared that, like many couples, they sometimes have strong disagreements. Both have different opinions, including about how Charles manages his time while undergoing cancer treatment.

“I think probably, particularly at the moment considering the King’s health in the last year, the main issue is that she can’t persuade him to take time out,” the friend noted.

“She obviously worries about him and his [cancer] treatment. Except for the first couple of months, he’s pretty well worked every day since.”