And it just so happens to be from their time on tour in Australia and New Zealand back in 2014.
The beautiful image was captured by photographer Steven Woolf and shows Prince George resting comfortably on his mother's shoulder after a cute play date in Wellington.
"She said it was just lovely and that it was her favourite photo of the tour," Steven revealed.
The Kiwi snapper later went on to gift Kate with a black and white print out of the photo - which she loved!
Check out Prince George's surprisingly adult habit below!