Prince Harry's biographer has revealed the "turning point" in his burgeoning romance with Meghan Markle came when the pair jetted to Jamaica for a friend's wedding.
Katie Nicholl said the couple's loved-up trip to the Caribbean isle in March 2017 for the nuptials of Tom Inskip helped cement their relationship, according to the Daily Mail.
Speaking on ITV's Lorraine, the author of Harry: Life, Loss, and Love, told how the prince's close friends joked that the couple would be next to walk up the aisle.
Describing Harry as "the man of the moment", she said: "The inner circle realised at that point that this was going to do the distance. They'd never seen Harry so happy."
Just eight months later, their 'drunken prediction' came true when the pair announced their engagement.
Nicholl, who started writing the book before the couple announced their engagement, also told how friends began hinting that the relationship "had legs" and was getting more serious by the day towards the end of 2017.
She also revealed the moment Meghan knew that Harry was "the one", after he bought presents for the children of her close friend Jessica Mulroney.
"It was the moment she fell in love with him," she said, explaining that the Mulroneys had "hidden" the couple away in their Toronto townhouse when news first broke of their relationship in late 2016.
"They were very much protectors, two of the few people who knew about their romance in that early stage," Nicholl said.
"Meghan's flat was under siege. The Mulroneys were very instrumental in hiding them in their townhouse and protecting them."
The couple, who will tie the knot at St. George's Chapel, Windsor Castle, on May 19, have already put in a number of joint public appearances ahead of their nuptials.
And Nicholl believes it is Meghan's ease in front of the cameras that makes her the right partner for her Harry.
"You only need to watch her on those early engagements that she's done [to see] her confidence.
"She's not as resistant to the cameras. Whereas for [Harry's exes Chelsy Davy and Cressida Bonas] it was a massive issue. They didn't want that life."
And the writer hinted that babies could soon be on the cards for Harry and Meghan, adding: "Family is very much on the agenda.
"You only need to watch Harry with children to see that he will be a wonderful father. Meghan is 36, she's very maternal. She wants to start a family."
And speaking of Harry's transition from 'a boy into a man' she added: "Going to war was the moment that really changed Prince Harry. He came close to death on two occasions
"Serving on the front line helped him to understand the concept of Invictus; he's grown up and he's found himself. Look at him, he's so happy."