Happy birthday to King Charles, who is celebrating his 74th birthday!
MORE: Charles and Camilla break royal protocol for sweetest reason - after shock protestor attack
The day will be all the more poignant for the monarch, given that it is his first since he ascended to the throne.
WATCH: King Charles' Funniest Moments
In the weeks since the death of his "beloved mama", Charles has been incredibly busy and on Sunday, he led the royal family and the nation at the annual Remembrance Sunday service at the Cenotaph.
READ: Prince Harry makes surprise appearance – as royals gather on Remembrance Sunday
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His floral tribute to the fallen left at the memorial in Whitehall featured the words, "In memory of the glorious dead. Charles R."
In contrast, the King is expected to spend his birthday quietly and in private with his wife, Queen Consort Camilla.
The King is expected to spend the day privately with his wife
His milestone on Monday will be marked by the Band of the Household Cavalry performing Happy Birthday during the Changing of the Guard ceremony at Buckingham Palace.
READ: King Charles: The one thing he never leaves the house without
MORE: 10 photos that show King Charles' close bond with his sister Princess Anne
Gun salutes will also be fired across the capital in honour of his birthday for the first time, with the King's Troop Royal Horse Artillery firing 41 volleys from midday at London's Green Park, and immediately afterwards the Band of the Scots Guards will perform Happy Birthday in the park.
An hour later the Honourable Artillery Company will fire a 62-gun salute at the Tower of London.
Prince William and Princess Kate sent their birthday wishes for Charles
Prince William and Princess Kate were among the very first to honour the King on his birthday.
A lovely new photo shared on their official Twitter account showed a Charles laughing, along with the message: "Wishing a very happy birthday to His Majesty The King!" His special day was also acknowledged on the Royal Family's social media account.
READ: King Charles has a very special wish for his granddaughter Princess Charlotte
MORE:16 photos that show King Charles' special bond with his grandchildren
It comes after the King and the Queen Consort broke royal protocol for the sweetest reason last week.
Charles and Camilla held hands with little Jason Tweedie-Long
Jason Tweedie-Long, who is just five, is seriously visually impaired - but was anxious to see the King and Queen Consort during their visit to York.
Knowing he wouldn't be able to from the crowd, he wrote to York Council who spoke to Buckingham Palace – and they made his wish come true.
Photos showed little Jason beaming in a multi-coloured raincoat and even holding hands with the King and his wife, with Charles seen beaming down at the youngster.
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