The Story Behind Princess Diana’s Iconic See-Through Skirt Photos Revealed 44 Years Later

When Lady Diana Spencer chose her outfit on the morning of September 17, 1980, little did she know that it would become one of her most famous looks. But Prince Charles's new girlfriend—dressed in a purple sweater vest and lavender blouse with a patterned midi skirt—went on to make a splash in U.K. papers with the now-iconic shots of "Shy Di" showing off her legs.

Former royal correspondent Charles Rae, who wrote for The Sun during the heyday of Charles and Diana's relationship, shared his insights on the famous photos in The Daily Mail on Tuesday, Sept. 17.

The royal expert said that since the royal girlfriend had been photographed "very few" times before her leggy look, "two journalists from rival newspapers were told by their editors to find out more about the young 19-year-old."

"They decided to join forces and knew she worked for a nursery somewhere in Pimlico," Rae wrote, adding the pair eventually found out she worked for the Young England Kindergarten.

"A deal was agreed that in return for her posing for a picture, she and the kindergarten would be left in peace," he noted.

On Sept. 17, "around half a dozen photographers and a few reporters turned up and Diana went with them to a nearby park," per the royal expert, who added that Diana "insisted" on bringing two young students with her for the shoot.

"As she posed, one of the photographers asked her to turn round and face in the opposite direction as the sun was shining on her face," Rae wrote, explaining, "One must remember at this point that there were no digital cameras in those days. They only shot film which had to be sent back to the office to be developed."

Diana— who wasn't wearing a slip under her skirt—turned so the sun was behind, causing its rays to illuminate "her legs like a spotlight," Rae wrote.

"The photo session with the amazing silhouette picture lasted no more than two or three minutes," Rae wrote, and since the photographers had to wait to develop the photos, they "could only speculate what the picture would be like" at the time.

Of course, "they had all managed to get that great picture which was splashed over all the front pages the following day."

As for Diana, she wasn't quite as thrilled as the people working in newsrooms across in the U.K.

Rae wrote that Lady Diana "was appalled" by the snapshots "and moaned to Prince Charles, 'I don't want to be known as the girlfriend with no petticoat.'"

Although she initially got the nickname of "Shy Di," the royal commentator wrote that the princess—who married the now-King Charles in July 1981—eventually found her fortitude.

"She had bloomed from a shy young bride into a strong, outspoken woman not afraid to fight her corner," he wrote.

And forty-four years later, the sheer skirt trend is everywhere, proving the fashion-forward princess was always ahead of her time.