From her engagement to Prince Charles as a shy teenager to her roles as doting mother, humanitarian and global celebrity, Diana's turbulent life still captivates people around the world.
Young, beautiful and fun, she seemed refreshingly informal when she married the heir to the throne in 1981 at age 20, after what the media and palace officials portrayed as a fairytale romance.
But the acrimonious breakdown of her relationship with Charles, during which every salacious detail was played out in the world's newspapers, would shake the monarchy to the core and drive her to self-harm.
For many people the public image of Diana remains fixed as she was in an extraordinary 1995 interview in which she spoke out about her feelings over her husband's affair with Camilla Parker Bowles, her own infidelity and her history of self-harm.
The way she spilled secrets, stripping the monarchy of its mystique and casting doubt on Charles's ability to be king, drew horror in some parts of the British establishment.
But for many ordinary people, her troubles -- revived once again in a slew of new documentaries and interviews -- made her only more popular.
"Like Marilyn Monroe, she has frozen in time. She was like a creature locked in a piece of amber. There forever -- beautiful, young, vulnerable and damaged," said royal biographer Penny Junor.
- 13 dates before marriage -
Born on July 1, 1961, Diana grew up in an aristocratic family with ties to the monarch -- her father worked for the late king George VI and Queen Elizabeth II.
She grew up with three siblings, in a childhood marred by the bitter break-up of her parents.
She left school at 16 with no qualifications and went to finishing school in Switzerland, before getting a job in a nursery in London.
From the moment she was linked to Charles, however, her life changed.
The prince was under increasing pressure to find a bride, and at the age of 32, he proposed -- perhaps too soon.
Diana said they only met 13 times before their wedding.
She quickly fulfilled her primary duty as princess, with the birth of an heir, William, the following year, followed by Harry two years later.
Diana was a hands-on, adoring mother, and also possessed a remarkable empathy that drew people to her. Coupled with a strong sense of style, she rode a wave of popular and media enthusiasm for the monarchy.
She used her position to champion some of the most marginalised groups in society, shaking hands with patients with AIDS and leprosy, who were viewed as pariahs at the time.
But beneath the surface she was in turmoil, plagued by bulimia and wracked by self-doubt made worse by the feeling that her husband did not love her -- and the rest of the royals did not care.
- Crossed a line -
Rumours that the marriage was in trouble broke into the open in 1992, after Andrew Morton lifted the lid on Diana's misery with a revelatory book, tactically endorsed by the princess herself.
That year ended with the bombshell announcement that the royal couple would separate.
The scandal only deepened with further recriminations and allegations appearing in the media, before first Charles and then Diana admitted to being unfaithful.
In her 1995 interview with the BBC's Panorama programme, Diana gave her version of events, admitting her affair with army officer James Hewitt, but also criticising the royals and questioning her husband's ability to be king.
This crossed a line. A few weeks later, the queen, who had already publicly expressed her sadness at the situation, wrote to both Charles and Diana urging them to seek a divorce.
On August 28, 1996, the divorce was granted and Diana was stripped of her title of Her Royal Highness. The fairytale was over.
- 'Queen of people's hearts' -
Still a princess, Diana remained in the public eye.
She found new love in Dodi Fayed, the son of millionaire businessman Mohamed Al Fayed, who was also killed with her on August 31, 1997, as their car was chased by paparazzi through the streets of Paris.
The outpouring of public grief was immense.
Millions of flowers were left outside her home at Kensington Palace, and thousands lined the streets of London to pay their last respects at her funeral.
Much of the popular anger over her death was directed at the royal family, fuelled by the queen's initial refusal to return to London to greet the crowds, and there was a surge of republicanism.
Two decades on, public support for the monarchy is as strong as ever and Charles -- with Camilla -- has to a large extent been rehabilitated.
But neither will likely ever match the popularity of his first wife, the self-styled "queen of people's hearts".