The King has accepted a patronage at Gordonstoun, his former school in Scotland, to mark the first anniversary of his coronation.
Charles has become patron of the Gordonstoun Association, a role previously held by his father Prince Philip, the late Duke of Edinburgh, who also attended the school.
It marks the King’s first official link with the Moray institution, which he attended from 1962 to 1967.
Charles secured five O-levels and two A-levels at the school, earning him a place to study archaeology and anthropology at Trinity College Cambridge.
During his coronation celebrations last year, he chose four pipers from the school to welcome him to St Giles’ Cathedral in Edinburgh for the Honours of Scotland ceremony.
The Gordonstoun Pipe Band also regularly takes part in the annual Braemar Gathering in Aberdeenshire, which is attended by the King.
Charles joins the Princess Royal as an official supporter of the school, with Anne holding the role of warden at Gordonstoun.
“As our most prominent former student, His Majesty exemplifies so many of the qualities we seek to instil in our students, notably a lifelong commitment to service.
“That His Majesty has chosen a patronage of our alumni body is a great honour both for the school and all members of the Gordonstoun Association.
“We look forward to His Majesty’s engagement and support with the association and its members in the years to come.”
Heather Woodward, chairwoman of the association, added: “The aim of the Gordonstoun Association is to promote and strengthen pupils’ links with each other and the school.
“There is no person more suited than the King to highlight the unique experience of what it means to be a former student of Gordonstoun, and I am therefore delighted that His Majesty has accepted patronage of the Gordonstoun Association.
“Although it’s almost 60 years since His Majesty attended Gordonstoun, his duty to service is an example of how the ethos and values of the school teaches students to think about others rather than themselves.
“We are looking forward to engaging with the King on his views on how we can further the aims of the association.”