King Charles III has taken on new responsibilities since he acceded the throne upon the death of his mother, Queen Elizabeth II. Like the late Queen, the former Prince of Wales will have a chance to celebrate two birthdays each year as per a royal tradition which was introduced 250 years ago.
The new King of the United Kingdom and 14 other Commonwealth realms will celebrate his 74th birthday on November 14 - but next year, he could celebrate two with the other being in June. Since 1748, Kings and Queens have marked their special day with the Trooping the Colour parade.
But Edward VII, who reigned from 1901 to 1910, was born in November - which wasn't the best time of year for a huge outdoor celebration.
Instead, he moved Trooping of the Colour to May or June because there was less chance of it being cold and drizzly on the big day.
The monarch after Edward VII - George V - helpfully had a birthday in June, but the Queen's father, George VI, whose birthday was in December, reintroduced the tradition of an official birthday, which Elizabeth II continued.
There wasn't a set date for the Queen's official birthday, and it was instead typically held on the second Saturday of June.
George VI used to do it on the second Thursday of the month, but the Queen changed it to the weekend for convenience.
Trooping the Colour, a military parade which dates back to the 17th Century, is a highlight in the royal calendar.
It sees more than 1,400 soldiers, 200 horses and 400 musicians to perform for the Monarch.
The most famous moment from the annual celebration is when the entire royal family come together on the Buckingham Palace balcony to wave to well-wishers.
It's normally the only time we get all generations of the Royal Family - including King Charles III, Kate, William, George, Charlotte and Louis together.
You can leave your tributes to Queen Elizabeth II here .
