Princess Diana was a sartorial icon, one who displayed an ability to pull off everything from make-it-look-effortless athleisure fits that brands are still trying to imitate today to a sultry “revenge dress.” Now, one of Diana’s most famous pieces is headed to the auction block at Sotheby’s: her “Black Sheep” sweater that she wore to one of her then-husband Prince Charles’ polo matches in 1981, thought by many of her adoring fans to be a symbol of her feeling of ostracization from the royal family.

The sweater was produced by knitwear label Warm & Wonderful until it was taken out of circulation in 1994, and, according to W Magazine, Diana was so enamored with it that when she found a tear in her personal sweater she had her secretary reach out to the brand to request another one. Since the Princess wore the sweater, it’s become something of a cult favorite: it’s in the permanent collection of the Victoria & Albert Museum in London, actress Emma Corin wore a replica of it in the fourth season of The Crown on Netflix (shown below), and its original designers Joanna Osborne and Sally Muir partnered with Rowing Blazers for a reissue in 2020 as part of the brand’s Diana-inspired collection.

Until recently, however, the original sweater worn by Diana was thought to be lost. Then, Osborne and Muir made a fortuitous discovery. “This past March, as we were rummaging through the attic searching for an old pattern, we spotted a small box,” they said in a statement. “Inside, tucked away beside a cotton bedspread, was Diana’s original red sheep sweater from 1981. Now, almost four decades later, this one-of-a-kind sheep sweater is ready to make its way into the hands of a fortunate collector.”

Now, after the discovery, the piece is serving as the crown jewel of Sotheby’s forthcoming Fashion Icons sale and is expected to fetch a price of between $50K-$80K USD.The sale is set to take place this September, but online bidding runs from August 31 to September 14, the day after New York Fashion Week ends.

For more from the world of fashion, check out Hypebeast’s roundup of the most exciting footwear moments from Paris Fashion Week SS24.