The Duchess of Cambridge has been hiding personalised copies of her photography book around the UK

Catherine revealed she and the 'Hold Still' judges, as well as participants in the project, had been hiding books around the UK in a video shared on social media.

A video of the duchess putting one copy next to a fountain by Kensington Palace was posted alongside a tweet which read: "Let the search begin! We’ve joined @the_bookfairies 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. #HSbookfairies.'

"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!(sic)"

A tweet from The Book Fairies - an organisation launched in 2017 to encourage people to share their books - revealed another of the books had been hidden outside Darent Valley hospital, while other images showed the tome nestled among flowers in a green field, propped up by a post box adorned with balloons and nestled on a cafe chair.

The images featured in the book were originally chosen for an online National Portrait Gallery competition from over 31,000 entrants.

Catherine launched the initiative in May 2020, asking people in the UK to submit their photos that captured their time during lockdown.

Proceeds from the sales of the book will be split between the National Portrait Gallery and mental health charity Mind.