They may be Royals, but at the end of the day Prince George and Princess Charlotte are just children – as they demonstrated today.
The cheeky pair, who welcomed little brother Prince Louis in April, were spotted at the window of Buckingham Palace watching the RAF 100 flypast at around 1pm.
And little Charlotte couldnt resist sticking her tongue out at crowds while stood alongside her brother – who also pulled a face or two.
It wasnt the first time Charlotte showed her cheeky side either after being spotted at Prince Harrys wedding in May poking out her tongue as she arrived for the service.
The young pair were joined today by Spanish nanny Maria Borallo as they watched the display.
The rest of the Royal Family were out in force for the service at Westminster Abbey to mark the centenary of the RAF.
Harry, Meghan, William and Kate joined the Queen, other prominent members of the royal family as well as Prime Minister Theresa May at the beginning of a day of events.
The Duke of Cambridge arrived in his No 1 uniform of the Royal Air Force, as well as his RAF wings in recognition that he is a qualified RAF pilot.
The Duke of Sussex also wore his No 1 RAF uniform, with RAF Regiment shoulder flashes, in recognition of RAF Honington – the home of the RAF Regiment – and also for his role as Honorary Air Commandant of the base.
This afternoon, thousands of people lined the palace approach in central London, to watch a ceremony hosted by the Queen and culminating in the historic flypast of bombers, old and new, along with spy planes, helicopters and transporters.
The Queen watched Typhoons form the shape of the number 100 in the sky, before the Red Arrows, the RAFs aerobatic team, concluded the show, vapour-trailing the red, white and blue of the Union Jack flag.
Heir to the throne Prince Charles and his wife Camilla, his son Prince William and wife Kate, and Prince Harry and his wife Meghan, all joined the queen on the palace balcony for the display.
The tribute to the RAF, which became the worlds first independent air force when it was founded as a separate entity from the British Army and Royal Navy in 1918, began with a service at Westminster Abbey.
The queen, dressed in a royal blue outfit with turquoise edging, later hosted a ceremony to present the RAF with a new Queens Colour, at which she recognised the services work.
Tenacity, skill and gallantry have been your hallmarks, she said.
I remember the Battle of Britain being fought in the skies above us and we shall never forget the courage and sacrifice of that time, she added, referring to the decisive encounter between the air forces of Britain and Nazi Germany over southern England in 1940.
Some of the veterans were due to attend the celebrations on Tuesday, including Wing Commander Paul Farnes, who flew in the Battle of Britain, and Air Commodore Charles Clarke who was shot down over Germany during the war.