As Leslie explained, the speculated content, which is said to focus on the princess’s mental health, eating disorders and her unhappy marriage, may prove to be too much for her sons.
“[The series] might provide closure, or it might-open new wounds for the sons. It all depends on who is going to speak to the camera and what they might reveal,” Leslie said.
“Most people who are royal watchers already know that what really broke Diana’s heart was her husband’s marital infidelity: his relationship with Camilla, which began years before he met Diana and never ended; and which drove her into the arms of other men.”
The royal author went on to claim that Diana and Charles’ divorce would have had a serious impact on the then young princes emotional wellbeing.
“It doesn’t matter that they were princes; that’s not an emotionally healthy situation for any child.” She said.
What’s more, a source reportedly told The Sun that both the royal family and Diana's Spencer family will refuse to take part in the explosive series.
"William and Harry will be very upset and angry. It's particularly distressing for Harry because he's been working with Netflix," the source told the publication, referring to his Thomas the Tank Engine special with the streaming service.
"At a time when the royals have been dealt a blow with Harry and Meghan leaving, the timing is not good."
News of the proposed Diana documentary comes after Prince Harry previously shut down the possibility of The Crown depicting him and Meghan.
Earlier this year, royal biographer Angela Levin claimed that Harry would "stop" any coverage of his relationship with Meghan being broadcast on the show, which dramatises the lives of the royal family.
Speaking to BBC Breakfast Angela said: "Harry, when I went to interview him at the Palace, the first thing he said to me when I shook his hand was, 'Are you watching The Crown?'
"I hadn't been at the time, I felt very embarrassed and I got it and he said, 'I'm going to make sure I stop it before they get to me,’” she added.