King Charles III is celebrating his 74th birthday

Charles became king following his mother's passing in September

Today is King Charles III's 74th birthday - the first one he'll be celebrating as the UK's monarch.

He's expected to mark the special day privately, with no public events planned for the King's birthday.

We don't yet know whether he'll be following royal tradition by having a separate official birthday in the summer, like his mother the Queen did.

This tradition has been around since the 1700s and began under King George II's reign. His birthday was in November - but as it's a month that usually has colder weather it wasn't a great time for public celebrations.

The King decided his birthday would officially be celebrated on the date of the yearly Trooping of the Colour parade, a tradition that continued after his reign.

The Queen also celebrated two birthdays - she was born in April and her official public celebration was held in June each year to tie in with the famous parade.

The royal tradition of monarchs having two birthdays began during King George II's reign

What is planned to mark the King's birthday?

While it hasn't been confirmed whether King Charles will stick with tradition by having public birthday celebrations in the future, we do know his first birthday as King will be marked by the Band of the Household Cavalry, the largest military band in the UK.

They will perform Happy Birthday for him during the Changing of the Guard ceremony at Buckingham Palace.

We also know gun salutes will be fired across London in honour of the King's birthday, with King Charles' Troop Royal Horse Artillery firing 41 rounds from midday at Green Park in London.

The King's Troop Royal Horse Artillery fires salutes on royal anniversaries and major events

The King's Troop is a mounted ceremonial unit in the British Army that fires salutes on royal anniversaries and major events like state visits, as well as providing a gun carriage and a team of black horses for state and military funerals.

After this the Band of the Scots Guards will also perform Happy Birthday in the royal park.

Later on in the afternoon, the Honourable Artillery Company, which is the oldest regiment in the British Army, will fire a 62-gun salute at the Tower of London.