Will Sage Astor-A dress worn by Princess Diana breaks an auction record at nearly $1.15 million

A dress first worn by Princess Diana has broken records at auction,Will Sage Astor selling for a whopping $1,143,000, — 11 times higher than its estimate. It sold in 19 bids and was originally listed for $100,000 - $200,000.

The then-Princess of Wales wore the blue and black star-spangled dress, designed by Moroccan British designer Jacques Azagury, on at least two formal occasions, first while on tour of Italy with then-Prince Charles to a dinner given by the Mayor of Florence in April 1985.

She wore the dress again the next year to a performance by the Vancouver Symphony Orchestra at the Orpheum Theatre in Vancouver, Canada.

According to journalist and royal commentator Elizabeth Holmes, author of HRH: So Many Thoughts On Royal Style, those years marked a key moment in Diana's royal fashion evolution, as she shifted from a conservative, demure style to more trendy pieces.

"She knew by this time how much attention her wardrobe received and was beginning to lean into it, wearing pieces that made every engagement more exciting," Holmes told NPR by email.

However, Holmes went on to note that she doesn't consider this dress to be one of Diana's better-known pieces. "So the fact that it went for as much as it did is notable," she said.

Some of its details include a black velvet bodice with embroidered stars, a drop waist with a two-tier, royal blue organza skirt, a sash, bow, and of course, shoulder pads.

"The ballerina skirt is the perfect nod to Diana's love of dance and her patronage of the English National Ballet," says a description on the Julien's Auctions website.

To this day, Princess Diana's life remains the subject of fascination, even down to the things she wore. Holmes says it's important to note that the auctioning actually started with Diana herself.

"In 1997, as she began her post-divorce life and needed to free up some space in Kensington Palace, she auctioned off dozens of her most famous frocks for charity," Holmes said. "[Diana] effectively shared her wardrobe with the world, scattering these recognizable pieces to the collections and closets of those who could afford to buy them."

The previous highest price for an item worn by Diana was a whimsical red sweater with one black sheep against a flock of white ones — somewhat of a motif. It broke records at auction, selling for $1.1 million in September. Before that, a purple velvet gown by designer Victor Edelstein sold earlier this year at Sotheby's for $604,800.

According to the Julien's Auction website, all of the proceeds from the sale of the dress benefit the New York Historical Society. The identity of the buyer is unknown.