Royal Central editor Charlie Proctor has published a BBC video of two Royal siblings at a serious event where 69-year-old Charles played a little prank on his 68-year-old sister, Princess Anne.
The prince stealthily crept up behind his sister's back and apparently tickled the princess, after which they both shared a laugh.
The Queen is standing beside them, overlooking her children's amusing behaviour with her grandsons, Princes William and Harry.
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Princess Anne is known to be the hardest-working member of the Royal family for her regular attendance at different events with 455 official engagements in 2017 alone.