But in that moment, not everyone realized the deeper meaning stitched into the folds of her soft blue tulle gown.

More than fashion
Every time Princess Diana stepped out at a public event, all eyes were on her. Known as “The People’s Princess,” she radiated charisma—and when it came to style, she rewrote the royal rulebook. During the 1980s and ’90s, Diana became a global fashion icon, often opting for softer, more approachable looks over traditional royal formality.

One of her go-to style signatures? Pastels. These soft, elegant shades were a staple in her wardrobe, showing up in everything from tailored suits to flowing gowns.

One of Princess Diana’s most iconic fashion moments — though not as widely known as others — happened back in 1987.

Anwar Hussein/WireImage
Diana’s appearance at Cannes alongside Prince Charles was brief — just 10 hours in total. Officially, the royal couple were in Cannes to honor Sir Alec Guinness, support the British film industry, and attend a glamorous black-tie gala at the Festival Palace.

Intense security at the Gala dinner
Diana didn’t speak during the dinner — but she didn’t have to. All eyes, and every camera lens, were locked on her. That dinner became the most sought-after invitation of the entire festival. Security was intense, with ticket holders required to bring their passports for identity checks just to get in.

And when Diana she made her way into the screening of The Whales of August — most simply saw a princess in another stunning dress. Photographers captured her from every angle — her gown’s flowing chiffon scarf catching the breeze.

But it wasn’t just a glamorous photo op. Diana’s strapless, powder-blue gown, designed by her longtime collaborator Catherine Walker, was more than fashion.

Walker, the designer who would go on to define many of Diana’s most unforgettable fashion moments, crafted a gown that did more than turn heads—it quietly paid homage to another royal figure who had deeply impacted Diana. With its flowing lines and icy hue, the dress echoed the elegance of Princess Grace of Monaco, a woman whose tragic end had always lingered in Diana’s mind.

Anwar Hussein/Getty Images
The Philadelphia-born star, who was the epitome of class and beauty, retired from the big screen at just 26 years old to marry Prince Rainier III and become Princess of Monaco.

Five years before the 1987 Cannes Film Festival, Grace Kelly had tragically lost her life in a horrific car crash — the same heartbreaking fate Diana would meet just ten years later.

Barely a mention
Yet on that glamorous night in Cannes, few in the media seemed to notice the subtle tribute woven into Diana’s flowing pale blue gown, a quiet echo of Grace’s timeless, icy elegance.

Few realized that Diana’s gown was a subtle tribute to one of her earliest royal confidantes. At least, it wasn’t something the newspapers picked up on at the time— if you look through the 1987 archives, there’s barely a mention.

But today — and for a few sharp-eyed observers even back then — the connection feels obvious. The dress, with its icy blue tone and flowing silhouette, looked strikingly similar to the Edith Head gown Grace Kelly wore in Alfred Hitchcock’s To Catch a Thief, famously filmed along the French Riviera.

Grace Kelly wearing a light blue evening gown designed for her by Edith Head, for the 1955 film, ‘To Catch a Thief’.
That choice was no accident. Diana and designer Catherine Walker reportedly took direct inspiration from Grace’s screen presence — even down to the specific shade of blue, which Hitchcock himself had picked to evoke a sense of cool, untouchable beauty.

Diana and Grace Kelly shared a unique bond. Though their time together was brief, it left a lasting impression on Diana.

In 1981, just after her engagement, Diana had met Grace at a charity gala. Nervous and overwhelmed, the 19-year-old bride-to-be had broken down in tears in the ladies’ room. It was Grace, then 51, who held her close and offered the kind of advice only a woman who had lived through the royal machine could give. That moment stuck with Diana.

Diana and Grace at the The Royal Opera House on March 9, 1981 in London / Anwar Hussein/Getty Images
Cannes also had a special meaning for Princess Grace — it was there on the French Riviera that she, still an American actress at the time, met her future husband, Prince Rainier, in April 1955.

And 32 years later, as she stepped onto the same French soil where Grace had first met Prince Rainier decades earlier, Diana honored her quietly. No speech. No press release. Just fabric, color, and memory.

This striking accessory brought an airy, flowing quality to the dress, “catching the breeze that was high on the evening of the film screening,” as Newsweek described.

Two years later, Diana would re-wear the same gown to the premiere of Miss Saigon. And in 1997 — just months before her own tragic death — she included it in her famous Christie’s charity auction, where she sold 79 iconic dresses.

According to Tatler, Cannes gown sold for $70,700. It would later resurface at auction in 2013, fetching over $132,000, with the proceeds going to a children’s charity.

In 2017, the dress sat behind glass at Kensington Palace, part of a tribute marking the 20th anniversary of her passing. Now, it serves as a time capsule — not just of Diana’s style, but of her quiet depth, her grief, and her tribute to a woman who understood her pain better than anyone else.

On that windy Cannes evening, the photographers got the shot. But maybe not the whole story.