It’s telling that the lead image in the promotion of the final series of The Crown, a show ostensibly about Queen Elizabeth II and her ascendent line of heirs, is not of HRH. Instead, it’s an iconic shot of the person who's really at the centre of the Netflix show's sixth season: the late Princess Diana.

The photo in question has become embedded in popular culture since it was taken on Diana’s last holiday before her death. The ex-royal sits, pensively, on the diving board of a superyacht, looking out to sea in a turquoise swimsuit. But what is the true story behind one of the most famous images of the Princess Of Wales?

princess diana blue swimsuit the crown
Netflix/Getty Images

The backstory

In July 1997, Diana was on a Mediterranean holiday with her boyfriend at the time, Dodi Al Fayed, son of the then-Harrods’ boss, the late Mohammed Al Fayed. Diana and Dodi – and the Princes William and Harry – all spent time together in Castle St. Therese, Al Fayed’s 30-bedroom villa in St. Tropez in the South of France.

But Diana was called to Milan on 22 July, where she attended the funeral of her friend Gianni Versace, who was murdered by a fan on the steps of his Miami home on 15 July.

The author and friend of Diana, Tina Brown, later wrote: “The murder of the flamboyant fashion star Gianni Versace... while Diana was on Al Fayed's yacht, was a meteor shower in the exploding sky of her final summer.”

With the weight of the death of her friend still on her mind, in early August, Diana travelled alone to Sarajevo to publicise the fight against landmines in the country. Here, she came face to face with some horrific tales of mutilation of the people, and spent time working with rehabilitation groups of survivors.

By early August, after an emotionally turbulent few weeks, Diana was back on holiday with Dodi, this time on his yacht, known as Jonikal.

But on 10 August, pictures of Diana and Dodi kissing in Sardinia were published in the Sunday Mirror, and all hell broke loose; especially when it was claimed Diana could possibly be engaged, or even pregnant. In the trailer for series six, Imelda Staunton’s Queen is shown the front-page splash and told: “Interest in the princess’ private life is unlikely to die down any time soon”, and it’s likely that in real life Diana would have received a stern phone call from the palace.

From this point onwards, it only intensified the swarms of paparazzi clamouring for pictures of the pair on holiday. Video footage from the trip shows dinghies filled with men with long-lens pictures surrounding the yacht, desperate to catch another money-spinning shot of the couple together – with figures going as high as £1 million a photo.

diana blue swimsuit
API//Getty Images

The photo

On 24 August, Diana, dressed in just the teal swimsuit, took a walk out to the diving board of the yacht and sat down on it. She would have had a lot to process from the past few weeks.

She would also have known the press were desperate for pictures of her and Dodi together – perhaps she told him to stay below deck to protect him while she gave photographers a shot to appease them.

But according to one paparazzo in the documentary Sex & Power, the romance was just for show: “No-one knows this, so it’s ­actually quite interesting. [The crew member] said, ‘They don’t share the same bedroom, he calls her ma’am, is ­incredibly deferential and respectful. But as soon as she goes outside to wave to the paps, she’s bending over and kissing him and hugging him’... The truth [of their romance] is the opposite.”

Was this then another posed shot designed to reset the narrative, or was it simply a candid picture of the troubled princess in genuine thought? Whatever the case may be, the photo's melancholy pull is still being felt.

The first half of The Crown series 6 streams on Netflix from November 16.