THE Trooping the Colour paradecelebrates the monarch's official - but not actual - birthday.
But what is it exactly and why does the King have two birthdays?
What is Trooping the Colour?
Trooping the Colour is an event that takes place every year that dates back to Charles II in the 17th century when regiment colours trooped in front of soldiers so they could recognise their unit in battle.
At the start of it, the monarch is greeted by a Royal salute and the National Anthem.
The parade then commences and concludes with a second Royal salute.
Royals ‘brace for Meg memoir’ after Harry's book ‘to rip Wills & Kate’
His Majesty and other members of the Royal Family gather on the balcony at Buckingham Palace to watch a fly-past by the Royal Air Force.
Why do the Royal Family attend the Trooping of the Colour?
Each year the Royal family appear on the Palace balcony.
The first recorded royal balcony appearance was made by Queen Victoria in 1851, during the opening celebrations of the Great Exhibition.
It has since become an established tradition and a rare opportunity to see the Royal Family together in once place.
Why does The King have two birthdays?
The King traditionally has two birthdays, his actual birthday on November 14 and an official birthday marked every summer by the Trooping the Colour ceremony.
The "official" celebration takes place in June despite monarchs originally celebrating their birthday on the second Thursday in June, but the date was changed to the second Saturday in June in 1959. The reason this odd tradition began is typically British: namely, the UK's temperamental weather.
It was started by George II back in 1748 - because the weather was too bad to hold his Birthday Parade on the actual date in November.
Inside Camilla's £850k 'guilty pleasure' country pad - and Charles 'hates' it