Princess Diana and Prince Charles
Princess Diana and Prince Charles at the Chelsea Flower Show, London, May 1984. She is wearing a navy maternity coat by Jan van Velden. Getty Images/Jayne Fincher

Princess Diana secretly worked with Andrew Morton for her biography for a reason.

The members of the royal family had the shock of their lives when Princess Diana’s book “Diana: Her True Story” was published. The late Princess of Wales reportedly recorded tapes to hand over to Morton with the help of her friend James Colthurst.

In the Channel 5 documentary “Royals at War,” Morton described Princess Diana’s voice as similar to someone speaking from a prisoner cell. He also revealed why Prince Charles’ wife opted to work with him.

“She felt she needed to speak out,” Morton said, adding that he found Princess Diana “absolutely miserable” and “like a prisoner of the Palace.”

“Well, she chose me, thankfully, because I was independent and I was sympathetic to her cause,” the royal biographer said.

However, he admitted that he wasn’t prepared for the cascade of information provided to him, all the more for the controversy that the book aroused. Morton confessed that he was “surprised.”

Upon listening to Princess Diana’s recordings, Morton felt her “misery” and “unhappiness” that put him in total shock. He added that he felt like he “entered a parallel universe.”

In the same documentary, royal experts talked about Princess Diana’s rivalry with Sarah Ferguson. According to Lady Colin Campbell, the late Princess of Wales could be “very wily.” She added that Prince William and Prince Harry’s mom knew how to sex things up so she would come out of any situation smelling of roses.

Morton confessed that Princess Diana was furious when she learned that an uncomplimentary rival book was due weeks before their book’s publication. He advised her that they needed another “fact,” so the People’s Princess leaked Prince Andrew and Sarah Ferguson’s impending separation at the time which made Queen Elizabeth II furious with the Duchess of York.

The members of the royal family thought that Prince Andrew’s ex-wife handed the information to the press. Ferguson, herself, didn’t suspect that the source was Princess Diana.

Meanwhile, Lady Colin admitted earlier that prior to working with Morton, Princess Diana asked her to work with her for her biography. However, she declined because the princess wanted to play the victim and she sensed that it would do no good to her children and to the royal family.

Lady Colin said that Princess Diana wanted her to tell lies like propaganda. She didn’t want to criticize Morton, but she felt that he accepted Princess Diana’s words undiluted.