Princess Eugenie's wedding dress proved to be revealing, but not in the way one might think.

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Eugenie wore a long-sleeved, low-backed dress, custom-designed by British designers Peter Pilotto and Christopher De Vos, the BBC reported. The gown featured a open neckline that covered the shoulders and a low back, with a full-length train.

WINDSOR, ENGLAND - OCTOBER 12:  Princess Eugenie of York arrives for the wedding of Princess Eugenie of York to Jack Brooksbank at St. George's Chapel on October 12, 2018 in Windsor, England.

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Credit: WPA Pool

The low-backed gown revealed a long scar on Eugenie's back, from scoliosis surgery she had done when she was a child. The choice to show the scar was deliberate on Eugenie's part, who wanted to support others who have scoliosis, the BBC reported.

The princess told ITV in an interview prior to the wedding: "I think you can change the way beauty is, and you can show people your scars and I think it's really special to stand up for that."

Eugenie, a patron of the Royal National Orthopaedic Hospital, also reportedly invited her surgeon and other medical staff to the wedding, Vanity Fair reported, as a way to honor them. The surgery, which Eugenie said took eight hours, required the placement of titanium rods on each side of her spine. She spent three days in intensive care and another couple of weeks recovering during which she used a wheelchair, but after that, she was walking again, according to the hospital's website.

Scoliosis is a sideways curvature of the spine that occurs most often during the growth spurt just before puberty, according to the Mayo Clinic. While most cases are mild, some, like in Eugenie's case, require corrective surgery.

Eugenie, 28, married tequila brand ambassador Jack Brooksbank, 32, Friday at St. George's Chapel at Windsor Castle, with many royal family members in attendance.