The US Vogue editor shocked the fashion world in November 1988 when she put a model in jeans, an item that had never been worn previously in front cover shots.
Now, Wintour has revealed that the look came about because Israeli model Michaela Bercu had put on a bit of weight so she could not fit in the skirt that matched the Christian Lacroix top in the photo.
Wintour's debut Vogue cover in November 1988
Wintour wrote on Vogue's blog: "Michaela was wearing an haute couture Christian Lacroix jacket with a beaded cross, all very Like a Prayer, and stonewashed Guess jeans.
"The jacket was actually part of a suit, but the skirt didn't fit Michaela; she had been on vacation back home in Israel and had gained a little weight."
She added that it didn't matter that the model did not fit into the skirt, writing: "In fact, it only served to reinforce the idea to take couture's haughty grandeur and playfully throw it headlong into real life and see what happened."
She revealed that the magazine's printers had rang her to enquire if there had been a mistake, as the cover was so "unlike the studied and elegant close-ups that were typical of Vogue's covers back then, with tons of makeup and major jewellery'.
"I couldn't blame them," Wintour said. "This one broke all the rules."
She continued: "Michaela wasn't looking at you, and worse, she had her eyes almost closed. Her hair was blowing across her face.
"It looked easy, casual, a moment that had been snapped on the street, which it had been, and which was the whole point."
