AceShowbiz - Prince George and Princess Charlotte's cute and honest reactions during a Royal Air Force flypast were captured on camera. While the adults were dressing to impress and minding their manners during the Tuesday, July 10 event, the little royals were goofing off behind the window of Buckingham Palace.

In some images taken by paparazzi, the two siblings were seen watching the display from inside the palace walls with their nanny, Maria Teresa Turrion Borrallo, and an aide to their mother. The 4-year-old prince and his 3-year-old sister were sticking out their tongues, saluting and making silly faces during the celebration of the RAF centenary.

Prince George donned a snazzy blue polo shirt, while Princess Charlotte sported a bright blue dress for the occasion. They looked excited as their parents, Prince William and Kate Middleton, caught the action from a balcony.

Queen Elizabeth II, Prince Charles and his wife Camilla, as well as Prince Harry and his new wife Meghan Markle also stepped out for the event. While the Queen, Kate and Meghan opted for blue dresses in different hues, Camila wore a white dress.

Princess Michael of Kent, Prince Edward, Sophie Countess of Wessex, Prince Andrew, Princess Anne and Tim Laurence were among other British royals spotted on the balcony.

A day prior, Princess Charlotte also stole the spotlight with her cheeky gesture during Prince Louis' christening. As she left the Royal Chapel at St James' Palace in London, where the event took place, with her parents and her brothers, the young princess told photographers outside the building that they're not invited to her brother's party.

"You're not coming," she told the photographers as her father held her hand. The Duke of Cambridge appeared to hear what his daughter said and flashed a smile. Making sure the photographers didn't follow them, Princess Charlotte adorably kept a watchful eye on the media pack.