The King was officially welcomed to Balmoral on Monday in brilliant August sunshine.
Charles, 76, has taken up his summer residence at his Scottish abode and is expected to host family members in the coming weeks.
The monarch, dressed smartly in a tweed jacket and a tartan kilt, inspected the Balaklava Company, 5th Battalion, The Royal Regiment of Scotland, at the gates of the royal residence.
As part of the guard of honour, the King also came face-to-face with an infamously cheeky Shetland pony, Cpl Cruachan IV, who is the mascot of the Royal Regiment of Scotland.
The 16-year-old pony was famously told off by the late Queen Elizabeth II for nibbling on her flowers during a visit to Stirling Castle in 2017. But he was impeccably behaved as Charles stroked his nose.
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© PA Images via Getty ImagesMeet the mascot
Cpl Cruachan IV took up his role in October 2012 and met the late Queen on many occasions. He's proudly paraded at towns across Scotland, as well as royal residences, Balmoral, Buckingham Palace, St James's Palace and Windsor Castle.
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© PA Images via Getty ImagesThe King and Cpl Cruachan IV
There were no cheeky antics from the Shetland pony at the ceremony on Monday, as the King gently stroked his nose upon arrival.
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© PA Images via Getty ImagesGuard of Honour
Charles received an official welcome from the Balaklava Company, 5th Battalion, The Royal Regiment of Scotland.
They are expected to remain on royal guard at the residence for the duration of the King's stay.
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© PA Images via Getty ImagesInspection
Charles was in good spirits as he inspected the guard of honour.
It comes a day after he drove himself and the Queen to the Sunday church service at nearby Crathie Kirk.
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© PA Images via Getty ImagesWarm greeting
The King was also greeted by Lord Lieutenant of Aberdeenshire outside the gates of the castle.
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© PA Images via Getty ImagesMeeting the public
Charles took his time to greet and chat with members of the public, who had stood outside the gates waiting for the King's arrival.
In the coming weeks, Charles is expected to host several of his family members at Balmoral, including the Princess Royal, the Prince and Princess of Wales and their children, the Duke and Duchess of Edinburgh, as well as his nieces and nephews.
The castle has been the private Highland home of the royal family since 1852.
