It goes without saying that Princess Diana's wedding dress will go down in history as one of the most famous of all time. But, as any good style icon would, the late Princess of Wales had a backup option (or a "spare," if you will).

Elizabeth Emanuel, who designed both of Diana's dresses (with the help of her ex-husband David), shared a photograph of the never-before-seen gown with Hello! magazine. (She has previously shared sketches of the extra dress, but this is the first picture of the actual dress to come to light.) In the photograph, Elizabeth is seen working on a stitch of the other dress as it is laid across a table.

"The spare wedding gown was made just in case the secret of the real dress ever got out. Fortunately, it was never used," the designer told the outlet. "The dress was made in pale ivory silk taffeta with embroidered scalloped details on the hem and sleeves. Tiny pearls were sewn on the bodice."

As can be seen in the sketches, the alternative gown had a similar frilly and ruffled aesthetic to Diana's dress on her big day. It also contained a V-neck, quarter-length sleeves, and a ballgown skirt, all similar to the first one. "People always ask you what it was like," she continued. "It was similar in certain respects and both had the big skirt, but everything else was different. So it was really just a backup to the original."

She added, "[Diana] asked us to keep it very, very secret, which we did. But I think there was so much interest when she did actually wear the black dress that the press wanted to know who is designing her wedding dress and they had to announce it at that time."

The dress was just meant to be a second option in case Diana's first dress was leaked to the public, and it was never actually completed. Princess Diana never even tried it on, and to this day, Elizabeth isn't even sure where it is. "I don't know where it went," she said. "It just disappeared."

According to People, the dress that Diana did walk down the aisle in was made from silk taffeta and lace worn previously by Queen Mary (Queen Elizabeth's grandmother). Her famous train was a whopping 25 feet long; the longest train ever worn by a royal bride.