The Queen was left intrigued by the Tardis feature at the Chelsea Flower Show earlier this week.
As reported by Outpost Gallifrey last Friday, the Doctor's time-travelling police box - complete with light and sound effects - is the centrepiece of the display called A Garden In Time, which has been created by Cardiff Council landscape officer Mo Dorken and her team.
It shows the changes in the world since the start of the series in 1963 and includes a 1960s Cardiff rugby shirt and a Doctor Who annual with William Hartnell on the cover.
The Royal Family were exploring the Royal Horticultural Society's annual show on Monday and the Queen stopped off to look at the revolving Tardis.
It is in a "void" separating a 1960s urban garden from a modern one based around contemporary gardening ideas and styles, with an emphasis on sustainability, recycling and climate change.
"I was explaining how we were having a Doctor Who theme and a Sixties part of the garden because it was when the series first started."
Celebrities were also in attendance at the show on the eve of it opening to the public, including Joanna Lumley, who played the Doctor in the 1999 Comic Relief spoof The Curse of Fatal Death, written by Steven Moffat.