Diana’s unhappiness in the marriage was growing as Charles carried on a longtime affair with mistress Camilla Parker Bowles, and she decided to secretly tell her story through a biography.
“It explained Diana’s feelings, her sense of isolation, her sense of being a prisoner,” Andrew Morton, author of Diana: Her True Story, says in this week’s issue. “Once that leached into the popular imagination and people got to understand who she was as a three-dimensional character, then people responded to her.”
He added, “And you could see that people wanted the Diana monarchy, one that was more approachable, a bit looser. A little bit more empathetic to their own issues and problems.”
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Morton secretly interviewed Diana (through recorded tapes delivered by an intermediary) for his infamous book, which was published in 1992 — the year she separated from Prince Charles before their divorce was finalized in 1996. At the time of the book’s original publication, no one knew that Diana herself had provided the book’s source material. That remained a secret until after her death in 1997. After she died, Morton revealed his source to the public.
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Morton has since published several biographies on other famous figures, including royals such as Wallis Simpson (the book he was promoting when he collapsed) and Prince William, as well as celebrities like Tom Cruise and Monica Lewinsky. His latest book is a biography of Meghan Markle titled Meghan: A Hollywood Princess.
For more about the show and how women are shaping the House of Windsor, pick up the latest issue of PEOPLE on newsstands on Friday.
Ahead of the publication of Meghan: A Hollywood Princess, Morton spoke to PEOPLE about Meghan and Harry and how life in the royal spotlight has been difficult for Harry over the years.
“Being a royal has been a romantic curse for him,” Morton said.
Morton is one of many sources who speak in depth about the Queen, her family, the past and future of the royal family in The Story of The Royals, a two-night television event presented by PEOPLE, airs August 22 and August 23 (9:00-11:00 p.m. EDT) on ABC.