Prince Harry has revealed a faux pas by wife Meghan, who mistook his uncle, the Duke of York, for an assistant to the Queen.
The Duke of Sussex has uncovered several behind the scenes secrets of the Royal Family in memoir Spare.
Among its pages is a story from when he took Meghan to Royal Lodge, the home Sarah Ferguson shares with ex-husband Prince Andrew, in 2016, to meet his family.
Also in attendance was the Queen who quizzed the American on the upcoming presidential elections in the US.
However at the end of the get together, Meghan showed an extraordinary lack of knowledge about the senior royals when she mistook Prince Andrew for one of the Queen’s footmen.
Harry wrote: “My uncle Andrew, seated beside her, holding her handbag, began to escort her out.”
“After a moment Meg asked me something about the Queen’s assistant. I asked who she was talking about.”
When she replied “the man who walked her to the door,” the penny dropped for the prince who realised she had meant the Queen’s second son.
During the same meeting Meghan was asked by the Queen about her opinion of Donald Trump .
The Duke of Sussex said introducing his grandmother to his now-wife Meghan was "pleasant" and the late Queen looked "pleased".
During the meeting, which took place at Royal Lodge, the Duke of York’s Berkshire home ahead of the 2016 United States presidential election, Queen Elizabeth II asked Meghan about Trump, but she quickly changed the subject.
Writing about the encounter in his book, Harry said: "It was all very pleasant. Granny even asked Meg what she thought of Donald Trump
"Meg thought politics a no-win game, so she changed the subject to Canada."
The Duke of Sussex said his grandmother "squinted" and told Meghan "I thought you were American", to which Meghan replied: "I am, but I’ve been living in Canada for seven years for work."
The book added: "Granny looked pleased. Commonwealth. Good, fine."
Spare, which hit the shelves on Tuesday, was boosted into the record books with 400,000 hardback, e-book and audio format copies being snapped up, its publisher said.
The book included claims that the Prince of Wales physically attacked him and teased him about his panic attacks, and that the King put his own interests above Harry's and was jealous of the Duchess of Sussex and the Princess of Wales.
In a US broadcast promoting the work, Harry branded Duchess of Cornwall the "villain" and "dangerous", accusing her of rehabilitating her image at the expense of his.