Princess Diana
Princess Diana's third wedding gown disappeared mysteriously. Pictured: Princess Diana at Aintree racecourse for the Grand National on April 3, 1982. Getty Images/Hulton Archive

Princess Diana had a third wedding dress, but it mysteriously disappeared.

Elizabeth and David Emanuel have said that they designed a third bridal gown for the late Princess of Wales in case her first dress would be made public before her big day. They also made a copy of the first dress, which was given to Madame Tussauds after she tied the knot with Prince Charles.

However, the whereabouts of the third dress became a mystery. It suddenly disappeared before it was even finished, according to the designers. "It was only three-quarters finished — we simply didn't have time to make it in its entirety, so none of the embroidery or finishing touches were done," Elizabeth said (via Express). "It was hanging up in the studio for a long time, and then it disappeared. I don’t know if we sold it or put it into storage. It was such a busy time. I'm sure it'll turn up in a bag one day!"

Elizabeth added that Princess Diana was not aware of the third dress. She also never tried it on. It was just a backup to make sure that the People's Princess's wedding gown would be a surprise to the public.

"Had the secret of the real dress got out it's possible that Diana would actually have worn this one," she added. "We didn't try it on Diana. We never even discussed it."

Princess Diana almost ruined her wedding gown on her big day. The late princess previously explained that she decided to apply a final spritz of her favorite perfume before walking down the aisle, but she accidentally tipped the entire bottle all over the front of her dress.

"I've just put my perfume on and I've spilled some on the front of my dress. They'll kill me!" Princess Diana told her makeup artist, Barbara Daly.

The royal ended up tucking up the front of her gown as if she's lifting it in order to cover the stain. She was seen doing this in several of her photos during the royal wedding.

The members of the royal family usually keep their wedding dress and designer secret prior to the big day. Elizabeth said she understands this and supports this.

"They’re keeping quiet on the designer this time, probably to avoid all the hassle that we had," she told People. "It was really difficult and we didn’t have to contend with cameras in phones etc like you have today. How do you keep something secret like that? I have no idea."