See Prince William and Prince Harry's Fingerprints That Were Left Behind On Princess Diana's Dress 

Prince William and Prince Harry left their mark on one of their mom’s dresses!

Small fingerprints have been spotted on the late Princess Diana‘s green velvet dress, which will be on display at the princess’s former home of Kensington Palace next week in the exhibit,

The silk velvet evening dress, from designer Victor Edelstein, was only worn for private occasions in 1985 – when William was just 3 years old and Harry was barely 1 – so there are no public photos of Diana wearing it.

But some royal evidence remains in the form of fingerprints, experts believe. There is a “cluster of small indentations on the front of the skirt on this dress,” Historic Royal Palaces says in a statement. “Some historians have speculated they may be the fingerprints of the young princes, clinging to their mother’s legs.”

For the princes, who live at Kensington Palace, the exhibit is one of several that will help mark the 20

anniversary of their mother’s death in Paris in August 1997. They have also commissioned a statue and there are plans for a commemorative garden at the palace.

“We are neighbors with her sons and we have been keeping them informed as good neighbors do,” Eleri Lynn, curator at Historic Royal Palaces which is hosting the exhibition, tells PEOPLE.

“[Diana] is still such a relevant, cultural force that so people still come to Kensington Palace because it was her former home and to celebrate her life and style and to mark the anniversary we are presenting

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