On June 29, 1994, Princess Diana attended a dinner at the Serpentine Gallery in London, fully aware that her husband Charles would be admitting to his affair with Camilla that same night on TV.

Determined to make a lasting impression, she chose to wear a daring black dress by designer Christina Stambolian – and while it broke a string of royal protocols in the process, it did its job, and photos of the stunning Princess filled newspapers around the world.

Diana had owned the bespoke £900 dress for three years but had hesitated to wear it, worried it was too provocative.

However, the moment felt right, and she seized the opportunity, and in doing so cemented her place in fashion history.

The Princess accessorised her off-shoulder dress with a statement sapphire and pearl choker, which had been a gift from the Queen Mother on her wedding day in 1981.

Princess Diana wore her famous little black dress by Christina Stambolian to a charity dinner at the Serpentine Gallery on June 29, 1994

Diana had originally declined the invitation to the fundraising dinner, but changed her mind following Charles’s infidelity revelations.

In an interview with Jonathan Dimbleby, broadcast on ITV, the then Prince of Wales confessed to having an affair with Camilla after claiming that his marriage had ‘irretrievably broken down’.

Diana’s outfit was a last-minute choice, as she had originally planned to wear Valentino to the event.

However, to her dismay, the fashion house issued an unauthorised statement about the dress, prompting the royal to change her plans.

Instead, she opted for a striking off-shoulder black gown by Greek designer Christina Stambolian, which later, unsurprisingly, became known as the ‘revenge dress’ .

It featured a sweetheart neckline, ruched bodice and an asymmetric skirt with a sash cascading to one side.

And it defied protocol in several ways: its colour – royals are meant to avoid black unless in mourning – the form-fitting cut and its perceived inappropriateness for a gala. Diana completed the look by painting her nails a bold shade of red, further breaking royal traditions.

The dress, which broke royal protocol, featured a sweetheart neckline, ruched bodice and asymmetric skirt with a sash falling to one side

A much more demure Diana in 1981, as she and Charles announced their engagement to the world

Christina Stambolian recalls Princess Diana visiting her shop in 1991 and asking for a ‘special dress for a special occasion,’ in Claudia Joseph’s book, Diana: A Life In Dresses.

The royal was accompanied by her brother, Earl Spencer, following lunch at her favourite restaurant, San Lorenzo.

Diana told the designer: ‘I want a special dress for a special occasion. It doesn’t matter if it is short or long. It has to be something special.’

‘We sat down, and I drew a few sketches on a piece of paper,’ Stambolian continued.

‘The dress was revealing, quite short and showed quite a bit of leg and flesh. Diana was not sure about it. She thought it was a bit risqué. She wanted everything more covered up, longer and the neck higher.

‘I told her she had good legs, and she should show them. “Why not be daring?” I said. She asked her brother and he said: “Do what you think is right.” Finally, she said yes to the style, then we moved on to the colour. I had black in my mind, but she wanted cream.’

After sketching out several ideas, the pair settled on a mini dress that took two dressmakers more than 60 hours to create.

Greek designer Christina Stambolian sketched out the dress with Diana present, Claudia Joseph revealed in her book, Diana: A Life In Dresses

Stambolian did not see Diana again until the reception for the Christie’s auction, in June 1997, when Diana auctioned 79 of her most iconic evening gowns

Diana, wearing an embroidered mini dress by Catherine Walker, chatted to Stambolian at the auction

The dress hung in Diana’s wardrobe for three years, until she finally decided to wear it to the Serpentine Gallery.

‘I was very disappointed,’ Stambolian said. ‘Then I realised she had been waiting for the right occasion.’

Referring to one of Diana’s favourite ballets, Swan Lake, the designer added: ‘I was thrilled to see Diana wear it on that night of all nights.

‘She chose not to play the scene like Odette, innocent in white. She was clearly angry. She played it like Odile in black. She wore bright red nail enamel, which we had never seen her do before. She was saying, “Let’s be wicked tonight.”

Meanwhile, Anna Harvey, Diana’s former stylist, said: ‘She wanted to look a million dollars. And she did.’ The stylist also wrote in Vogue that it ‘thrilled’ the Princess to make an impact.

Stambolian did not see Diana again until the reception for the Christie’s auction, in June 1997, when Diana auctioned 79 of her most iconic evening gowns.

The famous little black dress was sold for £39,098 to Graeme Mackenzie and his wife, Briege, who owned the Body Shop franchise in Scotland.

They planned to exhibit it to raise money for children’s charities. So far it has garnered more than £39,000 for Children’s First by gracing an assortment of luncheons, balls and fashion shows.

The dress was notably displayed at the Museum of Style in Newbridge, County Kildare, in the 2017 exhibition Diana: A Fashion Legacy, where it was described as ‘the most important exhibit’.

A replica, made in 2010 by Stambolian, can be found in the Museum of Style Icons, in Newbridge, County Kildare, Ireland.