The Prince of Wales has tested positive for coronavirus.
Prince Charles, who is 71, is displaying "mild symptoms" but "remains in good health", Clarence House have said.
He has been self-isolating in Scotland with the Duchess of Cornwall.
The duchess was also tested for COVID-19, but she "does not have the virus", the statement said.
The royals' coronavirus tests were carried out by the NHS in Aberdeenshire.
"It is not possible to ascertain from whom the Prince caught the virus owing to the high number of engagements he carried out in his public role during recent weeks," Clarence House said.
Prince Charles' last public engagement was on 12 March, but he did have a number of private meetings with Highgrove and Duchy individuals, all of whom have been made aware.
A small number of people living and working at his Aberdeenshire residence will remain there and are self-isolating.
Charles has spoken to his sons the Duke of Cambridge and the Duke of Sussex, as well as the Queen.
A Buckingham Palace spokeswoman said: “Her Majesty The Queen remains in good health.
"The Queen last saw The Prince of Wales briefly after the investiture on the morning of 12th March and is following all the appropriate advice with regard to her welfare."
One week ago, amid coronavirus cancellations, the Queen met the commanding officer of HMS Queen Elizabeth at Buckingham Palace.
Prince Charles served in the Royal Navy and also trained as a jet pilot with the Royal Air Force..
In 2012, he was appointed a Field Marshal in the British Army, Admiral of the Fleet in the Royal Navy and Marshal in the Royal Air Force.
To mark his 71st birthday last November, gun salutes were fired by the King's Troop Royal Horse Artillery and Honourable Artillery Company.
In December, the Prince of Wales attended the commissioning of Britain's newest Queen Elizabeth-class aircraft carrier, HMS Prince of Wales, in his new role of Honorary Commodore-in-Chief, Aircraft Carriers.
Cover image: PA.