In When Sarah Met the Monarchy, royal author Tom Quinn explains Charles – along with his father Prince Philip, at first welcomed Prince Andrews wife “Fergie” thanks to her “sparkle”.
But her shine quickly became too bright for the future King, who is known for his dour moods.
“[They] had especially welcomed Sarah’s energy. She had, at first, seemed like this bright, positive young thing,” Tom explains.
“But it was just starting to sort of leak away. Charles apparently said, ‘Look, the problem about Sarah is you just can’t shut her up’.”
A source tells New Idea Royals Monthly that around the same time as his remarks, Princess Diana’s own warm feelings toward her sister-in-law began to cool.
“Along the same lines as Charles, Diana was worried Fergie was an ‘awful gossip who couldn’t be stopped’,” says our insider.
“And that was the end of the Windsor’s love affair with Fergie. Her marriage to Andrew started going off the rails after that.”
It’s long been rumoured that Prince Charles is not Fergie’s biggest fan.
“Charles is not OK with Fergie. He can’t stand her in reality,” a royal insider told The Sun in 2018.
“He thinks she’s brought embarrassment to the Royal Family in the past and his relationship with his brother has been strained as a result.
“They don’t get on personally. There’s so much baggage because he feels she sided with Diana over Camilla all those years ago.
“He looks at a royal like Lady Sarah Chatto (Princess Margaret’s daughter), an intellectual and someone who loves the arts, and thinks Fergie is no comparison.”
Meanwhile, Prince Philip is said to “not care at all” about Fergie and her relationship with Prince Andrew (who she married in 1986 and divorced in 1996).
“It’s stupid to say that the Duke of Edinburgh has any issue with Andrew and Fergie’s relationship. He really doesn’t care anymore, on any level,” the source said.