Princess Diana attends the Worshipfull Company of Fanmakers Banquet at Mansion House in December 1985.Photo:Tom Wargacki/WireImage

Princess Diana at Worshipfull Company of Fanmakers Banquet, Mansion House December 1985 at the Various in Various, United Kingdom.

Tom Wargacki/WireImage

Princess Dianacontinues to reign as a fashion icon, and a gown that exemplified her exceptional style will soon be available for sale.

“When I noticed that Diana and[Prince] Charleshad gone to the dance floor, I went and danced very close to them so that they would notice. As I remember it, Charles pointed it out to her and she laughed; it certainly wasn’t a big deal,” Fairweather said of the royal repeat in June 1985.

Princess Diana attends the Worshipfull Company of Fanmakers Banquet at Mansion House in December 1985.Tom Wargacki/WireImage

Princess Diana at Worshipfull Company of Fanmakers Banquet, Mansion House December 1985

“This was a gown that other people could purchase, but she chose to wear this gown again. I think what’s special about it is that most women who buy evening gowns wear them more than once, so there’s this relatable situation where she wore a gown that you could buy retail. Someone else was wearing it [at the party], but she still liked the gown enough that she decided to wear it again,” Houlton tells PEOPLE.

How Princess Diana’s Glamorous Gown Heading to Auction Showed She Was the ‘People’s Princess’

“There are different elements of her supporting British designers, people referred to her as a ‘People’s princess.’ She did things that were often relatable, she wasn’t just always doing things that only someone in her position could do. That’s what makes this gown specifically special,” the expert says.

Nineteen-year-old Lady Diana Spencer famously wore the Warm & Wonderful jumper (British parlance for a pullover) with jeans to then-Prince Charles' polo match in June 1981, one month before theirroyal wedding.

Princess Diana in a Wonderful & Warm sheep sweater in June 1981.Tim Graham Photo Library via Getty

Princess Diana

The fashion statement put British brand Warm & Wonderful on the map, and designers Sally Muir and Joanna Osborne received a letter from Buckingham Palace a few weeks later. A secretary said Diana had damaged her whimsical jumper and asked if it could be repaired or replaced. A new sweater was sent and the original became forgotten — until Osborne stumbled upon it in storage this winter.

Princess Diana in a Warm & Wonderful sheep sweater at Prince Charles' polo match in June 1983.Princess Diana Archive/Getty

Diana, Princess of Wales (1961 - 1997) with Major Ronald Ferguson (1931 - 2003) at a polo match at Smith’s Lawn, Guards Polo Club, Windsor, June 1983

Princess Diana Archive/Getty

The letters Buckingham Palace sent to Warm & Wonderful to coordinate the sweater swap are also included in the auction, and Houlton speculates that the “rare, never been-to-market” nature will elevate the allure — and demand.

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Letter, Sheep Sweater, How Princess Diana’s Glamorous Gown Heading to Auction Showed She Was the ‘People’s Princess’

On what makes the collection cohesive, Houlton tells PEOPLE, “They’re all unique, one-of-one pieces that kind speak to the wearer, the time, who that person is, and that’s ultimately what our sale is about.”

source: people.com