There are few figures who the fashion industry has canonised quite like Carolyn Bessette-Kennedy. The Calvin Klein publicist and her husband John F. Kennedy Jr died in a plane crash in July 1999, at the peak of their influence as the most stylish couple in New York.

The fascination with CBK’s wardrobe has endured in the 25 years since the tragedy. Bessette-Kennedy’s style was revered for its simplicity; she epitomised classy and classic minimalism and favoured timelessness over trends. She was a public figure for a relatively short while before her untimely death (she began dating Kennedy in 1994, they married in 1996) meaning that the limited amount of public and paparazzi photographs in existence serve as a specific cache of inspiration for fashion designers. As a compilation, they capture a woman at a particular moment in time, with a crystalised sense of her own taste.

For the first time ever, a piece from Bessette-Kennedy’s wardrobe is up for auction. Bonhams will sell her Yohji Yamamoto black silk dress on June 27 as part of its Collecting Classic Luxury online sale. The piece is symbolic, says Marissa Speer, Bonhams’s US Head of Sale for Handbags and Fashion, and it is expected to fetch far more than its $3,000 estimate.

“Whenever I come across pieces to sell, I always get excited, but this was a real ‘pinch me’ moment,” Speer tells The Telegraph. “Everyone who works in fashion recognises the name Carolyn Bessette-Kennedy and many view her as the ultimate fashion icon who defined 90s minimalism. I knew this was a once in a lifetime opportunity to present such a special Yohji Yamamoto dress directly connected to CBK.”

Bessette Kennedy had a special, personal relationship with the Japanese designer Yamamoto. His was one of just a few labels that she would regularly wear – she was similarly loyal to Manolo Blahnik, Miuccia Prada and Ann Demeulemeester. Speer notes that the quality of the piece hasn’t faded at all in the 26 years since CBK wore it to Manhattan’s private member’s venue The Supper Club, where she was photographed alongside Lee Radziwill, Jackie Kennedy’s sister. It is a wrap-style ‘trench dress’ with innovative hybrid design elements.

Bonhams will sell the dress on behalf of Sasha Chermayeff, a close friend of John F. Kennedy Jr since school, who was given the dress as a gift by Lisa Bessette after her sister died. 

“They were wonderful people,” Chermayeff says, “I was honoured to have known them. After 25 years, it is the right time to pass on part of Carolyn’s legacy.”

Speer predicts a great deal of interest from atypical buyers, as well as museums and institutions. Its seemingly low estimate of $2-3,000 will pique the interest of a wider audience. Many designers today, such as Mary-Kate and Ashley Olsen at The Row, Gabriela Hearst and Catherine Holstein at Khaite, draw direct influence from Bessette Kennedy’s pictures, and could see value in owning a piece like this. Modern celebrities who aspire to achieve the fashion prestige that  Bessette-Kennedy once did may also consider buying it to wear as a red carpet statement.

“I could see interest from design companies who want to keep the dress as inspiration in their archive,” Speer says. “Alternatively, there is the fashion angle, people who are inspired by Carolyn Bessette-Kennedy’s style and not forgetting of course, the Kennedy connection. It’s important not to forget the significance of the design itself and the Yohji Yamamoto Japanese fashion fans, this dress stands on its own as a highly coveted piece of 90s fashion design.” 

In the last year, a new book CBK: Carolyn Bessette Kennedy: A Life In Fashion was released, dissecting every image of Bessette-Kennedy alongside commentary from Edward Enninful and Michael Kors. Kors suggests that CBK was “a modern answer to the timeless American chic of her mother-in-law, Jacqueline Kennedy Onassis.” Her social media fanclub exists – there are Instagram accounts dedicated to her outfits – @carolynbessette has more than 58,000 followers. 

This auction will be an interesting test – it’s the first time that something Bessette-Kennedy owned or even wore is up for public sale, and the interest in her legacy will be measured on a very public stage. Future fashion exhibitions, documentaries, or dramas, may all be commissioned off the back of a big success.

Speer’s personal excitement is palpable and she seems confident in a strong result. “We look at Carolyn’s style today and the images look as if they could have been taken yesterday,” she says. “It is no surprise that she continues to pave the way as inspiration.” 

“I believe she was about anti-conformity in her own way,” she adds. “Going against seasonal trends and heavily logo-based designs, she invented minimalism. I believe she was the most elegant rule breaker fashion has ever seen.”