See the Secret Note Kate Middleton Left in Books Hidden Around London

Typed on Kensington Palace stationary, the letter is addressed to "Finder"

Catherine, Duchess of Cambridge
Kate Middleton. Photo: Neil Mockford/GC Images

Kate Middleton new photography book comes with a personal message for some lucky readers.

The Duchess of Cambridge stepped out in London on Friday to mark the release of her new book Hold Still: A Portrait of Our Nation in 2020, which features poignant photos taken amid the COVID-19 pandemic.

Kate shared footage on social media from her outing in support of The Book Fairies — a U.K.-based organization with the purpose of sharing books, leaving them in places for people to discover — in conjunction with the release of her book. The royal took part in hiding 150 copies of Hold Still in secret locations around the U.K., according to the release, placing a book near the fountain at Kensington Palace.

Twitter user Krish and his housemate found a copy hidden in London's Van Gogh Walk, sharing a photo of the note from Kate inside.

Typed on Kensington Palace stationary, the letter is addressed to "Finder."

"The Hold Still book documents a photography project which captured a portrait of our nation as we lived through the first COVID-19 lockdown last year," Kate wrote. "The images tell the stories of the challenges we all faced, but also how we came together in the most extraordinary of times."

"I am proud to have worked closely with the National Portrait Gallery on this project, and thrilled that the Book Fairies across the country are returning the images to the communities at the heart of Hold Still," she continued.

The note also came with special instructions to share the book: "Once you have finished looking through the book, please leave it somewhere else in your community for the next person to enjoy."

The note was signed, "With my very best wishes, Catherine."

Hold Still, on sale now, features 100 portraits reflecting the many different faces of individual experiences amid the COVID pandemic. Proceeds from the book raised will be split between leading mental health charity Mind and the National Portrait Gallery.

Over the past year, Kate has spoken to many of the 100 Hold Still finalists — and Kensington Palace shared one of those phone calls — on Kate and Prince William's new YouTube channel! — on Thursday.

In August, Kate spoke to 4-year-old Mila about her photo, called "Shielding Mila," which showed the little girl waving to her dad from the other side of a window. Mila and her mother, Lynda, had to isolate away from Mila's father, Scott, and big sister, Jodi, to protect Mila while she was receiving chemotherapy for acute lymphoblastic leukemia.

Kate spoke to Mila about her own three children and after learning Mila's favorite color is pink, the royal mom promised to wear a pink dress when they someday met.

The Duchess of Cambridge talks to 'Hold Still' entrants during a visit to the archive in the National Portrait Gallery

Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

The Duchess of Cambridge during a visit to the archive in the National Portrait Gallery

Kate learned it was actually Lynda's mother who encouraged her to submit the photo.

"I'm very grateful," Kate said. "And also for sharing such a personal time. You know, it'll be an image that is part of a national archive, and you know, it tells a story of this particular time and a very personal story too, so thank you so much for sharing it."

Related Articles