How King Charles III is celebrating his 74th birthday, 1st as Britain's monarch

King Charles III: As Prince of Wales, King Charles III was sometimes away on official foreign tours during his birthday.

King Charles III is celebrating his 74th birthday and his first as Britain's monarch on Monday. The monarch is expected to mark the day privately as there are no public engagements planned. There has been no announcement made so far of the his birthday being a separate official birthday in the summer, BBC reported.

King Charles III: Britain's King Charles attends the state funeral and burial of Britain's Queen Elizabeth, in London, Britain. (Reuters File)

Since the 1700s, monarchs with a non-summer birthday have had a second tied in with the Trooping the Colour parade. Even the date of Queen Elizabeth II's official birthday was always scheduled for a Saturday in mid-June and saw the announcement of the annual Birthday honours.

King Charles III's first birthday as monarch will be marked by the Band of the Household Cavalry performing Happy Birthday during the Changing of the Guard ceremony at Buckingham Palace. Gun salutes will also be fired across London in honour of his birthday as the King's Troop Royal Horse Artillery will fire 41 volleys from midday at London's Green Park and the Band of the Scots Guards is also set to perform Happy Birthday.

The Honourable Artillery Company will fire a 62-gun salute at the Tower of London although little is known about what King Charles will be doing.

As Prince of Wales, King Charles III was sometimes away on official foreign tours during his birthday and would celebrate it overseas with a cake, BBC reported.