• Prince Diana told Stewart Pearce that it would be amazing if their work would become a book someday
  • The late Princess of Wales permitted her former voice coach to write a book, but it should be published after her sons are married
  • Pearce believed that the late royal gave the condition to give her sons enough time to be stable in love with the brides they chose

Princess Diana allowed her former voice coach, Stewart Pearce, to write a book about her work with him on one condition and he followed it.

The late royal permitted Pearce to publish a book about their work together that's why he is working on his upcoming book "Diana: The Voice of Change." However, she had one condition for him to publish it.

"Diana said to me shortly before she died, 'Wouldn’t it be amazing if all of the work that we’ve done together became a book, but if you do, please don’t publish it until after the boys are married,'" the author told Us Weekly.

Prince William married Kate Middleton in 2011. Last month, the Duke and Duchess of Cambridge celebrated their 10th wedding anniversary. Meanwhile, Prince Harry and Markle exchanged "I dos" in 2018 and will be celebrating their third wedding anniversary Wednesday.

Pearce believed that the late Princess of Wales had the best intentions when she asked him to delay the release of his book.

"I feel that she wanted them to be stable in the love that she wanted for them with their chosen bride," he explained. "That was the meaning that I put to it — that it was to do with a level of that they could begin to then reflect through their wives on the possibility of all of the exercises that I include within the book."

He also pointed out Prince Harry's reluctance in opening up about the pain he endured following his mom's passing. The Duke of Sussex told Dax Shepard in his "Armchair Expert" podcast that it was Markle who saw his pain and convinced him to get help.

Pearce understood that Princess Diana wanted to delay his book because "she was literally waiting for them to move into that level of emotional resonance themselves, where there was a level of emotional intelligence that they could review her life from and therefore see her not as a weak vessel, but to see her as being the brilliant, sensitive and intensely excavated woman that she was."

The voice coach is convinced that it's the best time to step up. He also mentioned the similarities between Prince Harry's mom and wife when it comes to being a "voice of change."

"Also, with all the things that are going on with Harry and Meghan, I thought it was really important to step forward and say, ‘OK, well, their mother was one of the first great voices of change,’" he continued. "And now Meghan is becoming another great voice of change and [here’s] how we can support them and how we can support [all women] in this endeavor."

Pearce also said that Prince Harry reminded him of his late mother, Princess Diana. The late royal's ex-voice coach said the mother and son share the same rebellious spirit and they both search for a quality of balance in their lives.

Prince Charles and Princess Diana
Prince Charles and Princess Diana are pictured attending a centenary service for the Royal College Of Music on Feb. 28, 1982 at Westminster Abbey, London. Fox Photos/Hulton Archive/Getty Images