But it upset Clarence House that confirmation of the rumours dominated the news cycle and took the limelight away from Charles and Camilla’s tour.
According to the co-authors, Charles was “disappointed” with the timing of the announcement but understood that a “tipping point” had been reached with Harry’s relationship with Meghan.
The book said: “A statement from Kensington Palace condemning the press and, in the same breath, confirming Harry’s new girlfriend would all but eliminate coverage of Prince Charles’s tour of the Gulf.
“The Palace decided to go ahead with the statement nonetheless, much of which was drafted by Harry himself.
“Charles learnt of it just 20 minutes before it went out. Sure enough, as soon as Harry put out his declaration, the statement dominated the news cycle.
“The team at Clarence House, which had spent months putting together Prince Charles’s tour in the hopes that it would be covered significantly, was crushed.”
The book is due to be published by HQ on 11 August.