Prince George and his sister, Princess Charlotte, were front and center to watch a fly-past of aircrafts by the Royal Air Force -- and Peter and Autumn Phillips' daughter, Savannah (the granddaughter of Princess Anne), hilariously made sure to keep them in check.
Fans couldn't take their eyes off the 7-year-old, who amazingly deadpanned to the camera as she silenced Prince George with her hand over his mouth. Another shot shows Savannah using a different tactic to get her point across, as she gives George a big shushing.
It wasn't all sitting in silence, however, as Savannah loosed up her seemingly tight grip for a moment of celebration.
Also present on the balcony was Queen Elizabeth, William and Kate, Prince Charles, Prince Harry and his new wife, Meghan Markle -- who broke royal protocol by wearing an off-the-shoulder ensemble to the event. Prince Philip and Kate and William's third child, Prince Louis, were not in attendance.
Prince George and Princess Charlotte made quite the impact at Meghan and Harry's royal wedding last month. See more in the video below.