King Charles, Princess Anne behave like 'naughty little children' at 74

King Charles and Princess Anne have shown their mischievous side in public lately indicating they are still young at heart.

A sweet moment between the brother and sister was shared by Charles Proctor, royal journalist, on Facebook

"Prince Charles sneaks up on Princess Anne. Not something I would recommend," he captioned the clip.

Speaking about the adorable video, body language expert Judi James then told Express.co.uk: “These photos and this clip probably define the ongoing and now growing friendship between Charles and his sister.

“At a formal function Charles seems to sneak up behind Anne to tap her on the wrong shoulder to make her jump.

“Two of the most high-ranking and often rather pompous royals then dissolve into giggles, leading to Charles then delightedly continuing to entertain his sister so they become like two naughty children again.”

Judi continued, speaking about the foundation of the King's relationship with his sister: “This ability to offer Charles an escape route back into his childhood must form a strong base to their friendship but in Anne he also has a professional friend too.

“Anne’s work ethic and her total understanding of and adherence to a more traditional style of royalty must be something Charles will value highly now his parent’s generation are no longer there to uphold it," she concludes.