Princess Diana continues to reign as a style icon, and a robe that exemplified her distinctive model will quickly be out there on the market. 

Early Thursday, Sotheby’s introduced {that a} black and white strapless Murray Arbeid robe that the late Princess of Wales wore twice in 1985 can be included in its inaugural Vogue Icons public sale, opening subsequent week. Princess Diana first wore the timeless model to the Midsummer Evening’s Ball held in honor of Prince Edward’s twenty first birthday at Windsor Fortress — and was ever gracious when she met one other visitor in the identical outfit!

In line with Vogue, partygoer Natasha Fairweather additionally wore the taffeta quantity by the British model and approached the princess to see how she’d react.

“After I observed that Diana and [Prince] Charles had gone to the dance ground, I went and danced very near them in order that they might discover. As I bear in mind it, Charles pointed it out to her and he or she laughed; it actually wasn’t a giant deal,” Fairweather mentioned of the royal repeat in June 1985.

Cynthia Houlton, Sotheby’s International Head of Vogue and Equipment, completely tells PEOPLE that the fascinating twist is that the Princess of Wales reached for the Murray Arbeid costume once more quickly after. Diana sported the search for the Worshipful Firm of Fanmakers Banquet at Mansion Home that December, styling it with sapphire and diamond earrings, a press release sapphire, diamond and pearl choker (a favourite mixture she wore to the White Home!), black gloves and a burst of white feathers. 

“This was a robe that different folks might buy, however she selected to put on this robe once more. I believe what’s particular about it’s that almost all girls who purchase night robes put on them greater than as soon as, so there’s this relatable state of affairs the place she wore a robe that you may purchase retail. Another person was sporting it [at the party], however she nonetheless appreciated the robe sufficient that she determined to put on it once more,” Houlton tells PEOPLE. 

“There are completely different parts of her supporting British designers, folks referred to her as a ‘Individuals’s princess.’ She did issues that have been typically relatable, she wasn’t simply at all times doing issues that solely somebody in her place might do. That’s what makes this robe particularly particular,” the professional says.

Whereas the curve-hugging Murray Arbeid look has moved via public sale earlier than, it is going to be offered alongside one other piece from Princess Diana’s closet with extra uncommon provenance. In June, Sotheby’s introduced that the princess’ unique crimson sweater with a much-discussed black sheep motif would headline the Vogue Icons sale throughout New York Vogue Week.

Nineteen-year-old Girl Diana Spencer famously wore the Heat & Fantastic jumper (British parlance for a pullover) with denims to then-Prince Charles’ polo match in June 1981, one month earlier than their royal marriage ceremony.

The style assertion put British model Heat & Fantastic on the map, and designers Sally Muir and Joanna Osborne obtained a letter from Buckingham Palace a couple of weeks later. A secretary mentioned Diana had broken her whimsical jumper and requested if it could possibly be repaired or changed. A brand new sweater was despatched and the unique grew to become forgotten — till Osborne stumbled upon it in storage this winter.

“We checked out all images of her sporting it, and we in contrast the 2 and we each felt sure that it was the precise one. We simply knew as a result of each jumper is completely different, so it was simple to see. So we referred to as Sotheby’s!” Osborne completely instructed PEOPLE. 

The letters Buckingham Palace despatched to Heat & Fantastic to coordinate the sweater swap are additionally included within the public sale, and Houlton speculates that the “uncommon, by no means been-to-market” nature will elevate the attract — and demand. 

On-line bidding for Princess Diana’s unique crimson sweater opens Aug. 31 and can run to Sept. 14 via Sotheby’s. The jumper is in good firm, as certainly one of ten objects in Vogue Icons sale hooked up to trendy model icons.

Cannot get sufficient of PEOPLE’s Royals protection? Join our free Royals e-newsletter to get the most recent updates on Kate Middleton, Meghan Markle and extra!

Along with the late Princess of Wales’ Murray Arbeid frock and unique sheep sweater, Sotheby’s can be promoting Sarah Jessica Parker’s Chicken of paradise headpiece from Intercourse and the Metropolis: The Film, Michelle Obama’s classic Regular Norrell black lace costume from TNT’s “Christmas in Washington” particular in 2010, Kate Winslet’s Alexander McQueen for Givenchy night robe and bolero from the 1998 Academy Awards, the place she was nominated for Titanic, and Madonna’s classic Brussels lace veil from the primary Vainness Honest “Icons Situation.”

On what makes the gathering cohesive, Houlton tells PEOPLE, “They’re all distinctive, one-of-one items that sort converse to the wearer, the time, who that individual is, and that is in the end what our sale is about.”