Beyond her own extraordinary transformation, Morton credits Princess Diana for reshaping the image of the monarchy and shifting the culture. "William and Harry have been so fearless and I am very proud of them", Queen Elizabeth wrote in the letter.
One major issue in the divorce process was Diana's right to maintain the royal title "princess of Wales", without which she would lose any connection to the royal family and would have to curtsey to her ex-husband and their sons, the princes William and Harry. "It was handsome at the same time, and it was awesome now looking back at it", Harry added.
The previous year, a picture of a forlorn-looking Diana sitting in front of the Taj Mahal mausoleum - Mughal emperor Shah Jahan's monument of love to his favourite wife, Mumtaz Mahal - prompted rumours about the state of her marriage during a tour of India.
Last month, William joked she would have been a "nightmare grandmother", adding he keeps her memory alive with his children. These tapes were said to be recorded by Diana and her therapist at the time in secret before sending them to Morton. "This sounds really wrong but she wasn't centre of attention on this occasion".
Diana's own mum left when she was just six. "One of her mottos to me was, you know, 'You can be as naughty as you want, just don't get caught'". The broadcast from Buckingham Palace, which has become a defining moment of her monarchy, was clearly spoken from the heart by the Queen, who was dressed in black.
The one-time Met Police officer makes the raunchy claims in his new memoirs Guarding Diana: Protecting The Princess Around The World.
Several pieces were gifted to the late princess as a wedding present from the Crown Prince of Saudi Arabia, according to the Daily Mail, and two of the gems have even been repurposed by Catherine, Duchess of Cambridge.
"I think that what you might call Britain's stiff upper lip brigade ended with the funeral".
A controversial documentary showcasing tell-all tapes of Princess Diana has made Channel 4 the most watched channel this year, even though it's been heavily criticised for broadcasting them in the first place. But her brother is fighting for her to be remembered as a force for good in history.