For hundreds of years, British kings and queens have been able to mark two birthdays.
As well as their real birthday, marking the day they were born, they have benefited from an official or ceremonial birthday.
The official birthday, which features a parade called Trooping the Colour, is held in June, and dates back to George II.
The monarch's official birthday
The practice of an official birthday for the monarch dates back 260 years, when George II repurposed the traditional Trooping the Colour for his own celebration.
George II’s actual birthday was in November, and the monarch was fed up with terrible British weather putting a dampener on any plans.
So he decided to combine his birthday with the Trooping the Colour, a military procession which was held every year and already a fixture of the British calendar.
Queen Elizabeth II’s father, King George VI, had his official birthday on the second Thursday in June, and the Queen adopted this for a few years after she acceded.
But in 1959, she decided to change it to the second Saturday in June.
It just so happens that her official birthday isn’t too far away from her coronation day, but the two aren’t linked.
Trooping the Colour involves more than 1,400 parading soldiers, 200 horses and 400 musicians, who perform with military precision.
The parade moves between Buckingham Palace, The Mall and Horseguards’ Parade.
It’s also the time of year we get the famous balcony pictures as all the Royal Family waves to the crowds and watches the RAF flypast, which marks the end of the event.
The Queen used to ride on horseback with the parade to carry out the inspection but now arrives by carriage.
The Queen’s real birthday
Elizabeth II was born on 21 April 1926, the oldest daughter of the Duke and Duchess of York, who became King George VI and Queen Elizabeth when her uncle abdicated the throne.
In 2020 and 2021 the Queen has been in Windsor for her birthday. She is often in Windsor at this time of year for Easter Court but in the two years of coronavirus restrictions, there have been fewer official elements of this period in the royal calendar.
She reportedly spent her 94th birthday in 2020 video calling her family members. Her 95th birthday will be spent in mourning, as it comes just four days after the funeral of Prince Philip.
Her birthday has been marked privately for several years, and 2021 will see no official confirmation of any activities. It's reported she may have a quiet lunch with family.
One of the biggest parts of the Queen’s birthday celebration is usually a series of gun salutes in three places.
In London, a 41 gun salute is performed in Hyde Park, and a 62 gun salute at the Tower of London.
Closer to her Berkshire home, a 21 gun salute is normally held at Windsor Great Park.
A basic gun salute is 21 guns, and 20 are added if the salute takes place in a royal park, which is why it’s 41 guns in Hyde Park.
They are traditionally fired at 10 second intervals by the King’s Troop Royal Horse Artillery, a mounted ceremonial battery.
The Queen also gets gun salutes for her official birthday and her coronation day. They’re also fired for various events like royal births or for heads of state visiting.
There were no gun salutes in 2020 or 2021 due to the pandemic.
Watch: Queen Elizabeth's birthday won't be marked by gun salute