Prince George and Princess Charlotte charmed onlookers at the annual Trooping the Colour parade on Saturday.
The young royals were seen first peeking through the windows of Buckingham Palace before stepping out into the blazing sunshine for the Queen's Birthday celebration.
The Prince, who will turn four next month, and his sister Princess Charlotte appeared transfixed by the flypast, as they made their now-annual appearance on the palace balcony to wave to assembled crowds.
The 91-year-old monarch was greeted on Saturday by hundreds of well-wishers on a sunny day in the heart of ceremonial London.
She rode with her husband Prince Philip in an open carriage in the procession along Horse Guards Parade.
Prince William and Prince Charles were on horseback. William's wife Kate and Charles' wife Camilla were in a carriage with Prince Harry.
The Queen traditionally celebrates her official birthday in June when the weather can be balmy rather than in April, the month of her actual birth.
The day began on a sombre note when Elizabeth and Philip observed a minute of silence in honour of the victims of the horrific Grenfell Tower fire.
Telegraph, London; Reuters