Princess Diana Had a Secret Message Painted on the Bottom of Her Wedding Shoes

• Today marks the 40th anniversary of Prince Charles and Princess Diana's royal wedding, which has royal fans thinking back on the big day.
• One detail from the wedding that's getting buzz is that Diana had a secret message painted on the soles of her shoes—a small "C" and "D" for Charles and Diana.
• Clive Shilton, the cobbler who made the shoes, said she was also very concerned about the heel height. "Her main concern was that she wouldn't appear taller than Prince Charles, and because she was very tall–5'10"—the shoes would have to have a low heel," he said.

Prince Charles and Princess Diana's wedding was exactly 40 years ago today, and in honor of the anniversary, royal wedding fun facts and throwbacks are dominating royal headlines. One such fun fact: Diana had a secret message painted on the soles of her wedding shoes for the big day.

According to The Sun, Diana's wedding shoes were "beautiful suede heels with 542 sequins and 132 pearls in a sweet heart-shaped pattern." Diana requested that a final detail be added to the already-impressive shoes though, and had a small "C" and "D" painted on the bottom of the shoes as a secret message just for her and Charles on their special day.

Clive Shilton, the cobbler who spent six months working on the stunning heels, said the secret message wasn't the only request Diana made about the shoes for her wedding day. She was also very concerned about how tall she would be in the heels.

"[Diana] was a very shy, sweet, smiley-eyed young girl," Shilton told the Daily Mail. "Her main concern was that she wouldn't appear taller than Prince Charles, and because she was very tall–5'10"—the shoes would have to have a low heel."

The secret message has since been revealed to the public, as the shoes have been put on display. Even with the soles turned up, the "message" is still pretty hidden though. If you look very (very, very) closely, you can make out the "C" and "D" at the bottom of the floral design, right above the straight edge of the heel:

"No one even saw the bottom of the shoes, but it was important to us that they looked fantastic," Shilton said of the detail. "You would have seen much more of them if she'd tripped!"