Watch Prince Charles play a prank on his hard-working sister Princess Anne

By Jessica Pollack

Princess Anne may be the hardest-working member of the Royal Family, but her older brother Prince Charles can still crack her up. Though he turns 70 next week, the future king clearly hasn't lost his sense of boyish mischief! A new video tweeted by Royal Central editor Charlie Proctor shows a little prank he played on his 68-year-old sister, which was caught on tape by the BBC.

In the clip, the Prince of Wales sneaks up behind Princess Anne to startle her as the two attend a rather serious event. As visiting dignitaries are announced in the background, including "the Prime Minister of the Republic of Vanuatu" and "the Prime Minister of Jamaica," the siblings can be seen sharing a laugh as Charles makes a series of goofy hand gestures to the delight of his little sister. The Queen stands beside them, seemingly ignoring her children's antics with her grandsons, Princes William and Harry.

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While fans know Prince Charles to enjoy a good laugh, Princess Anne is a more buttoned-up member of 'the firm,' so seeing this side of her is an unusual delight. The royal is known for her unwavering work ethic, clocking a whopping 455 official engagements in 2017 - more than any other royal - and she's a shoo-in for hardest-working royal of 2018, too!

Prince Charles can always get a laugh out of his little sister, Princess Anne. Photo: © Getty Images 

Peter Phillips and Zara Tindall's mom has also made it clear that she has no patience for things she doesn't like - including the proliferation of smartphones and tablets at walkabouts. "I'm glad that I'm not starting now because at least you had people to talk to. Now you don't really. Phones are bad enough, but the iPads—you can’t even see their heads," she said during ITV's Queen of the World documentary. "No idea who you’re talking to. I either don’t bother or just say, 'Look, if you want to ask me something, I suggest you put that down.' It is weird. People don’t believe they’ve experienced the event unless they’ve taken a photograph."

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