Princess Charlotte entertained the crowd at a royal event by sticking out her tongue at a crowd of onlookers.
The four-year-old was with her parents Duchess Kate and Prince William, and brother Prince George, at the first King's Cup Regatta on Thursday.
The Royal couple had finished their yacht race and were walking through a glass hallway above the crowd with their children.
- Princess Charlotte captured mimicking the Queen's royal wave
- Princess Charlotte to begin nursery school with all-female staff
Duchess Kate encouraged her daughter to wave at the waiting fans - but Charlotte had other ideas.
The precocious pre-schooler stepped forward and rather than waving, stuck her tongue out.
The move prompted Duchess Kate to snap right into mum mode, yanking her daughter away from the window while laughing.
Video of the hilarious moment was posted on Twitter by The Royal Family Channel.
However, some commenters were less than impressed with Princess Charlotte's antics.
"Kate appears to laugh off Charlotte's behaviour," wrote one woman.
"My granddaughter would have been reprimanded for such rude, unacceptable behaviour."
Others compared Charlotte's attitude to how her father behaved at the same age.
"How absolutely hilarious and adorable! She takes after her father when he was little and an absolute stinker! His moniker was William the Terrible," wrote another.
Duchess Kate And Prince William hope the King's Cup Regatta will become an annual event to raise money for charity, and highlight the benefits of sport.
Adventurer Bear Grylls beat the two royals to victory, taking the King's Cup.