Prince William and Prince Harry would escape from London at their father King Charles' country home, Highgrove House, where the royal brothers had their own secret underground club and a specially-made treehouse.
And now the wooden hideaway in the gardens of Charles' Gloucestershire retreat has been given a very special makeover.
The treehouse was originally built in the late 1980s for the young princes in the historic Stumpery Garden at Highgrove and now it's been carefully re-thatched by an alumnus of The King's Foundation Building Craft Programme, to restore it to its former glory.
The treehouse, which was christened Hollyroodhouse House in a nod to its shape and the royal family's official Scottish residence, the Palace of Holyroodhouse, still contains a play tea set used by William and Harry when they were youngsters.
Take a look in the video below…
Ben Collyns, 36, was taught thatching as part of his studies with The King's Foundation, a charity which teaches traditional skills at education workshops on site at Highgrove.
Speaking about the project, he said: "It was an honour to have taken part in The King's Foundation's education programme in 2011 to 2012 and an even greater honour to be invited back to work on the treehouse at Highgrove Gardens.
"Studying with The King's Foundation helped establish my business and instilled a real sense of pride in my journey as a craftsman. Through the placements I worked on, I was not only able to learn new techniques but also build a network of friends and contacts that I'm still in touch with today.
"It is so important we continue to practice traditional skills to protect them for the next generation and I'm thrilled to be part of that movement alongside The King's Foundation."
Highgrove House was purchased by the Duchy of Cornwall from Maurice Macmillan, with Charles remodelling the Georgian house in 1987 to use it as a family home.
With the change in the line of succession in 2022, Prince William is now effectively his father's landlord as he now runs the Duchy. But Charles rents the house from the Duchy to use as a residence.
The treehouse can be seen on public garden tours at Highgrove, which run from April to October every year. Tickets for Spring 2025 will go on sale in the New Year.
For more information, visit highgrovegardens.com