Princess Charlotte isn’t shy about giving the crowd a silly greeting.

Her royal parents, Prince William and Duchess of Cambridge Kate Middleton, hosted a charity sailing race on Thursday, with their two eldest children watching the action from a boat nearby, People magazine reported. The 4-year-old and her big brother, Prince George, were alongside their grandparents, Mike and Carole Middleton.

KENSINGTON PALACE SHARES NEW PHOTOS OF PRINCESS CHARLOTTE

The inaugural King’s Cup regatta, hosted by William and Middleton, took place in Cowes, England.

Princess Charlotte of Cambridge and Catherine, Duchess of Cambridge having fun together after the inaugural King’s Cup regatta on Aug. 9, 2019 in Cowes, England. (Photo by Clive Mason/Getty Images)

The outlet reported that when Middleton, 37, brought her children to a window above the stage where their prizes were to be awarded, Charlotte stole the show by sticking out her tongue instead of waving. Middleton quickly went into mom mode and tried to stop the cheeky princess from being so mischievous.

Emily Nash, royal editor at Hello! Magazine, was quick to share a video of the adorable moment.

At uncle Prince Harry’s May 2018 to Meghan Markle wedding, Charlotte pulled the same move as her car arrived at St. George’s Chapel in Windsor Castle, the outlet shared.

KATE MIDDLETON REVEALS PRINCE GEORGE, PRINCESS CHARLOTTE SHARE HER LOVE FOR THIS HOBBY

Middleton, seemingly a hands-on parent, recently revealed that Charlotte and George share her love for photography.

Back in July of this year, Middleton attended a photography workshop and shared with the children and young people at the event some of her tips for capturing the perfect shot.

“Just look at everything around you. Maybe it’s in front of you, or far away but choose your subject and focus in on it,” she said, according to People.

Princess Charlotte of Cambridge and her mom Catherine, Duchess of Cambridge having fun together after the inaugural King’s Cup regatta hosted by the Duke and Duchess of Cambridge on Aug. 8, 2019 in Cowes, England (Photo by Chris Jackson/Getty Images)

“Get outside with your camera, as well. George and Charlotte love it when we do that,” she added.

PRINCESS CHARLOTTE TO ATTEND SAME SCHOOL AS BROTHER PRINCE GEORGE

Middleton often shares the photos that she’s captured of her children, and, according to People, is a self-proclaimed “enthusiastic amateur photographer.” In fact, photography was purportedly the focus of Middleton's thesis while she attended school at the University of St. Andrews.

Princess Charlotte and Catherine, Duchess of Cambridge attend the presentation following the King's Cup Regatta on Aug. 8, 2019 in Cowes, England. (Photo by Samir Hussein/WireImage)

Middleton’s attendance at the event came not long after Kensington Palace announced she is now the official patron of the Royal Photographic Society — a role that was passed down to her from Queen Elizabeth II, William’s grandmother.

Fox News’ Madeline Farber contributed to this report.