The King and Queen's senior equerry is set to leave his role supporting the couple.
Lieutenant Colonel Jonny Thompson has spent seven years with the royal household and is due to step down at the end of the year.
He will also leave the military and is expected to pursue a career in the private sector after more than 20 years as a soldier.
Lt Col Thompson was part of the King and Queen's entourage during their state visit to the United States in April.
He attracted a legion of royal fans online, who set up an Instagram account dedicated to the officer.
Lifestyle guru Martha Stewart appeared to meet him during a New York event celebrating the work of the King's Trust.
She posted on her Instagram: "We actually spoke while waiting for King Charles to get to us for a few words. Totally charming, completely cool. Exceedingly handsome."
Lt Col Thompson was commissioned into the Royal Regiment of Scotland in April 2006 and served in Iraq and Afghanistan.
He later took charge of Balaklava Company, the regiment's 5th battalion.
Lt Col Thompson led the ceremonial and military support for the late Queen's residence at Balmoral in 2018.
In December 2019, he became equerry to Charles and Camilla, King Charles' equerry in September 2022, and was promoted to senior equerry to both the King and Queen two years later.
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A Buckingham Palace spokesperson said: "Their Majesties were of course aware of this plan in advance and I know they are most grateful to Jonny for his support over the past seven years and wish him all the best for the future."
In July, King Charles' most senior aide, Sir Clive Alderton, announced he would step down after 20 years working in the royal household.
He played a leading role in the King's coronation and the response to various family scandals.
(c) Sky News 2026: King and Queen's senior equerry set to leave royal role
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