The official photograph shows King Charles in his new role as ranger of Windsor Great Park – a poignant appointment as the role was once held by his father, Prince Philip.
The Duke of Edinburgh was the longest serving Ranger of Windsor Great Park – holding the role from 1952 until his passing in 2021.
In the image taken last week, the king is seen leaning against an oak tree in the park and holding a wooden walking stick.
According to the royal family, the Ranger of The Great Park offers oversight and guidance to the Deputy Ranger and his team in the day-to-day stewardship of one of the country’s oldest estates.
King Charles is expected to spend today privately away from the public eye, with no official engagements planned.
During the changing of the guard outside Buckingham Palace this morning, the band of the Household Cavalry played Happy Birthday to the monarch.
Gun salutes will also be fired across London today, with the King’s Troop Royal Horse Artillery firing 41 volleys at Green Park.