The 30-year-old model took a break from sharing her usual fashion and beauty snaps to post a rare throwback photo of herself as a child – taken inside the grounds of Althorp House.
Kitty could be seen sporting short blonde hair and dressed in a yellow dress like Belle from Disney's Beauty and the Beast, complete with a white rose, tulle decorations and even the matching gold necklace which she held up to the camera.
She captioned the sweet image: "Accessorising on the move! Don’t know where I was going, but at least I wasn’t underdressed."
WATCH: Princess Diana's brother Charles Spencer shares new look at family home Althorp House
It wasn't long before fans reacted to the photo, with one simply commenting: "Adorable." A second added: "Outstanding outfit," while a third wrote: "This is the cutest picture ever!!"
In the background, the staff at Althorp House – the Spencer family estate – could be seen carrying what appears to be milk jugs, perhaps for afternoon tea.
Princess Diana grew up at Althorp House in Northamptonshire until she married the Prince of Wales in 1981. The property, which boasts 90 rooms and 550 acres, is now owned by her brother Charles, the 9th Earl Spencer, Lady Kitty Spencer's father. It is believed that Kitty's younger brother Louis will inherit the estate.
Lady Kitty Spencer and her brother Louis grew up at Althorp House
Prince Harry and Prince William's cousin now lives in a jaw-dropping home in London with her fiancé, Michael Lewis. As per Tatler, it is believed to be worth £19million, and Kitty recently told the Evening Standard that the interior design was her "most indulgent purchase".
"It was very important to me that my house was a home, somewhere I wanted to come back to at the end of the day, and somewhere that reflects who I am," she explained. "I became totally absorbed in the process, from the fabrics to the joinery. I can’t imagine that it’s something I’ll ever regret putting money into. After spending the majority of 2020 at home, I appreciate the space I’ve created now more than ever."