CNN  — 

Princess Diana wore many show-stopping outfits over the years, leaving behind an indelible impact on fashion history as it relates to royal dress codes, semiotics and more. From her unforgettable wedding dress to the black velvet cocktail dress, affectionately dubbed her “revenge dress” in the media, she wore in 1994 to even the pioneering penchant for athleisure she demonstrated throughout the ‘90s, Diana’s daring sense of style has become part of her lasting legacy.

But on Thursday in New York, the record for the highest price paid at auction for a garment worn by Princess Diana wasn’t broken by an elegant evening gown or rare designer accessory. Instead, it was country casual knitwear.

The piece: a “black sheep” sweater first worn by the late Diana when she attended a polo match in 1981, while she was engaged to the now King Charles III. It was the star lot at Sotheby’s latest Fashion Icons auction in New York, where it fetched $1,143,000, jumping from $190,000 to the final price in the last 15 minutes of the sale.

Previously, the record sale prince for a piece from Diana’s wardrobe was held by a Victor Edelstein ball gown designed for her in 1989. The strapless, maroon silk-velvet dress was fashioned with a shapely tulip skirt and was largely regarded as a pivotal example of Diana’s sartorial maturation. It fetched $604,800 at auction earlier this year.

But the quirky knit sold today has not only eclipsed that record sum, it has also become the most valuable sweater ever sold at auction. (This record was previously held by a cardigan word by Kurt Cobain during a Nirvana performance on MTV Unplugged, Sotheby’s said.)

Created in 1979 by knitwear designers Sally Muir and Joanna Osborne under their label Warm & Wonderful, the garment features a pattern of white sheep arranged in rows. One black sheep stands out from the crowd on the front of the sweater.

Sotheby's will be offering one of Princess Diana's most iconic looks -- the famous red and white wool Sheep Sweater -- this September in New York in its inaugural Fashion Icons auction, carrying an estimate of $50/80,000 (£40,000/70,000).  Much is already known about this beloved design and emblem of royal history, but a new part of the story will be revealed as it now appears at auction for the very first time.

However, just weeks after Diana had worn it, she reported a small snag in one of the cuffs, and it was returned to the label by Buckingham Palace. Muir and Osborne didn’t hesitate to knit her a brand new one, and later received a letter of gratitude from palace. Diana later ‘re-wore’ this replacement piece at the 1983 polo match pictured above.

The sweater was originally estimated to reach between $50,000 and $80,000, but after a total of 44 bids, the price reached 14 times higher than expected, according to Sotheby’s.

“We are thrilled that this cherished sweater has now found a new home, carrying with it the enduring legacy of Princess Diana,” said Muir and Osborne in a statement.

Correction: A previous version of this story incorrectly stated the duration of the auction.