John Galliano is a noted fashion designer who has a lot of experience designing outfits for top celebrities. But when he worked on Princess Diana's dress, the late royal completely left him in shock.

Recalling the incident in the Hulu docuseries In Vogue: The 90s, the 63-year-old said the Princess of Wales was invited to the Met Gala in 1996 by her friend Liz Tilberis, the editor of Harper's Bazaar.

The British designer was working with Dior at the time after he was selected to create a stunning look for Diana.

"I remember one day we all jumped into this old van, and we went to London, where we met Princess Diana. She'd been invited to the Met, and she would wear one of my dresses," he recounted.

"It was like a blessing. I mean like, wow," the former creative director of Givenchy continued. "We went to Kensington Palace and discussed drawings. I was trying to push for pink, but she was not having it. 'No, not the pink!' That was real, real fun."

For Diana's first and only appearance at the Met, John designed an eye-catching slip dress.

"So we did the dress and subsequent fittings, and it was beautifully done," adding, "correct" construction. 

In the background, the mother-of-two just had a high-profile divorce from King Charles, and she was in a rebellious mood, according to InStyle.

So, much to the shock of her designer, Diana opted out of the corset in the dress to make a fashion statement, the report said.

"Fast-forward to the event, and I just remember her getting out of the car," he remembered. "I couldn't believe it. She'd ripped the corset out."

"She didn't want to wear the corset," the iconic creator noted. "She felt so liberated. She'd torn the corset out. The dress was much more… sensuous," he emphasized, recalling her electric ascent up the Met steps.

"I mean, wow! Diana was my first couture client," John concluded.