Lady Diana Spencer in her iconic sheep sweater at Prince Charles' polo match in June 1981.Photo:Tim Graham Photo Library via Getty

Diana, Princess of Wales (1961 - 1997) wearing ‘Black sheep’ wool jumper by Warm and Wonderfu

Tim Graham Photo Library via Getty

Princess Diana’s iconic sheep sweater will soon be available for sale after it was discovered in storage over 40 years later.

The fashion statement put British knitwear 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 this winter.

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

Princess Diana

“I was in the attic in February searching for a pattern, and I just happen to notice this old wine box in a corner — and there was a red sheep jumper wrapped in a cotton bedspread. It was well preserved, and I had a kind of Groundhog Day moment and thought, ‘Could this be the one?’ I looked at the cuff which had obviously been sewn back on, and I called Sal and said, ‘I think I’ve found the actual real Diana jumper!’ ” Osborne exclusively tells PEOPLE.

“We had just sort of forgotten about it,” Muir echoes.

Princess Diana Warm & Wonderful Sheep Sweater

According to Houlton, what raises the stakes for the upcoming sweater sale is that the item has never come to market.

“They very randomly came across this sweater, it’s not like they were sitting on this sweater for some period of time and then decided who they should sell it to,” she said of Muir and Osborne.

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

Princess Diana

“Being at a polo match for Prince Charles in 1981, and then again in 1983, of course she was going to be photographed, of course that was going to be captured. I think that also really speaks to how much she really liked this specific pattern and this sweater,” Houlton tells PEOPLE, adding that “why she chose to wear this sweater in two very high-profile places” still sparks conversation today.

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

Though Muir and Osbourne never directly connected with Princess Diana and first learned that she wore their sheep sweater (which then retailed for $48) after seeing her photo in the newspaper, her support for Warm & Wonderful took the business to the next level. The Victoria and Albert Museum in London acquired one of the jumpers for its permanent collection in 1983, and Warm & Wonderful stopped producing the black sheep style in 1994.

Princess Diana and Prince Charles at his polo match in June 1983.Princess Diana Archive/Getty

Diana, Princess of Wales (1961 - 1997), Prince Charles and Sarah Ferguson attend a polo match at Smith’s Lawn, Guards Polo Club, Windsor, June 1983

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Fashion fans inspired to sport a lookalike of their own can preorder theDiana Edition Sheep Sweaterfrom Rowing Blazers ($248). Warm & Wonderful reissued the historic design to Jack Carlson and his label in 2020, bringing the timeless style to the next generation.

source: people.com