Prince Harry popped the question to Meghan Markle in November 2017 after dating for over a year, but Princess Diana's astrologer believes their romance was always written in the stars.
Debbie Frank, who met the late Princess of Wales in 1989, has claimed that she saw a US connection after reading the flame-haired royal's chart when he was just six years old.
The 33-year-old royal, who is currently fifth in line to the throne, is set to marry the LA-born actress, best known for her role in the US TV legal drama Suits, on 19 May at St George's Chapel in Windsor Castle.
"She'd be so happy that he was getting to marry the person he wanted to marry, that Meghan is such a different person," Frank told Royal Central. "She'd really admire Harry for bringing her in."
Frank said that she had a genuine friendship with Diana, who would "always have a giggle and a glint in her eye" when she talked about her youngest child.
"She would be rueful about him [Harry] and what was going to happen for Harry, and she knew he had all this energy, and it was going to be hard for him to conform to real life."
Diana was fatally injured in a car crash on 31 August 1997 in the Pont de l'Alma road tunnel in Paris, after her vehicle tried to flee paparazzi who were pursuing her on motorbikes.
Frank believes that had Diana been still alive she would have liked Markle because they are alike "in many ways". She added that the People's Princess would have been the perfect mother figure for her in England, with her own mother, Doria Radland, being thousands of miles away.
Harry met Markle, 36, for the first time in London 2016 when they were introduced by a mutual friend. In a break with royal tradition, they will say 'I do' on a weekend.