The Duchess of Cambridge teased royal fans on the day her photography book Hold Still was released.
In a clip shared to Prince William and Kate's Instagram account, the Duchess, dressed in a red coat, was seen placing a copy of the book outside Kensington Palace.
READ: Prince William reveals wife Kate Middleton is encouraging him to get into gardening for sweet reason
WATCH: Kate Middleton teases royal fans on day of book launch
The caption read: "Let the search begin! We've joined @bookfairies_uk for the day to share copies of Hold Still around the UK with you.
"Each copy is adorned with a gold book fairy sticker, gold ribbon, and has a letter from The Duchess tucked inside. To make this activity even more special, book fairies, the Hold Still judges and participants of the final 100 images are leaving copies at places that gave them hope during the lockdown.
"This special book documenting the unique collection of photographs goes on sale today in UK bookshops and online."
The Book Fairies is a literary movement which urges readers to share books which they have read and enjoyed by leaving them in public spaces for others to find.
MORE: The detail you might have missed in Prince William and Kate's birthday post for Archie
MORE: Prince William and Kate Middleton make major change to Instagram name
The Duchess placed a copy of the book outside Kensington Palace
Royal fans quickly took to the comments to share their excitement, with one writing: "I wish I could be the one to find. This is amazing!" Another said: "Such a lovely idea."
Recordings of the phone calls the Duchess made with finalists of the Hold Still community photography project have also been shared on William and Kate's new YouTube channel.
The Duchess took part in a moving phone call with Lynda Sneddon and her four-year-old daughter, Mila, whose photo was included in the project.
During the call recorded in autumn 2020, Kate made a sweet promise to the little girl that she would wear a pink dress when they were able to meet.
Hold Still: A Portrait Of Our Nation in 2020, £17.55, Amazon
The Hold Still book has been put together with support from The Co-op, which helped run the community exhibitions on billboards and outdoor poster sites in 80 towns, cities and areas last October. The final 100 images were first displayed in a digital exhibition on the National Portrait Gallery's website.
Net proceeds raised from the sale of the book will be split between leading mental health charity Mind, and the National Portrait Gallery. The funds will help to support arts and mental health projects across the UK, including Mind's work in local communities and the National Portrait Gallery's education and community projects.
HELLO!'s selection is editorial and independently chosen – we only feature items our editors love and approve of. HELLO! may collect a share of sales or other compensation from the links on this page. To find out more visit our FAQ page.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.