Diana, Princess of Wales (1961 - 1997) wearing 'Black sheep' wool jumper by Warm and Wonderful (Muir & Osborne) to Windsor Polo, June 1981. (Photo by Tim Graham Photo Library via Getty Images)
LONDON (AP) - A red sweater adorned with a flock of sheep worn by the young Princess Diana is expected to sell for more than $50,000 at auction.
The playfully patterned wool jumper featuring a single black sheep amid a pattern of white ones headlines Sotheby’s online Fashion Icons sale in September.
The 19-year-old Lady Diana Spencer was photographed in the garment at a polo match in June 1981, soon after her engagement to Prince Charles, who was then heir to the British throne.
RELATED: Duchess Sarah Ferguson diagnosed with breast cancer
Diana was already becoming a style icon —- and one of the world’s most photographed women — and the moment gave a big boost to designers Sally Muir and Joanna Osborne, who made the sweater for their small knitwear label Warm & Wonderful.
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. Diana is wearing a Muir and Osborne 'black sheep' sweater. (Photo by Princess Diana Archive/Getty Im …
A few weeks later, Muir and Osborne received an official letter from Buckingham Palace explaining that Diana had damaged the sweater and asking whether it could be repaired or replaced. The original was returned, showing damage to a sleeve the designers thought might have been caused by snagging on Diana's diamond and sapphire engagement ring.
This browser does not support the Video element.
Remembering Princess Diana: 25 years later | LiveNOW from FOX
Fans of the late Princess Diana placed tributes outside the gates of her Kensington Palace home on Wednesday, marking the 25th anniversary of her death in a Paris car accident. Diana died on Aug. 31, 1997, at the age of 36, stunning people around the world who felt they knew the princess after seeing her successes and struggles play out on TV screens and newspaper front pages for 17 years. The tributes left outside Kensington Palace on Wednesday were a small reminder of the mountains of flowers piled there in the days after Diana’s death.
A new sweater was knitted and dispatched, and Diana was photographed wearing it with white jeans and a black ribbon tie at an event in 1983.
RELATED: Prince Harry and Meghan's Spotify deal ends after agreeing to 'part ways'
Some have speculated Diana liked the "black sheep" pattern because she felt like an outsider in the royal family. Emma Corrin sported a replica as the young Diana in season four of "The Crown."
Diana, Princess of Wales (1961 - 1997) attends a polo match at Smith's Lawn, Guards Polo Club, Windsor, June 1983. She is wearing a Muir and Osborne 'black sheep' sweater. (Photo by Princess Diana Archive/Getty Images)
Warm & Wonderful still makes a cotton version of the design, which sells for 190 pounds ($250). Osborne discovered the original lying forgotten in a box in an attic earlier this year.
Cynthia Houlton, Sotheby’s global head of fashion and accessories, said "this exceptional garment, meticulously preserved, carries the whispers of Princess Diana’s grace, charm, and her keen eye for fashion."
The sweater, which has an estimated price of $50,000 to $80,000, will be on display at Sotheby’s New York showroom from Sept. 7-13. Online bidding opens Aug. 31 and runs to Sept. 14.
RELATED: Prince Harry testifies in UK court against tabloids accused of phone hacking
The record for a piece of Diana memorabilia is $604,800 for a Victor Edelstein-designed ballgown sold by Sotheby’s in January.