The Prince of Wales has tested positive for coronavirus.
He is displaying mild symptoms "but otherwise remains in good health", Clarence House has said.
A Clarence House spokesman said: "He has been displaying mild symptoms but otherwise remains in good health and has been working from home throughout the last few days as usual.
"The Duchess of Cornwall has also been tested but does not have the virus.
"In accordance with Government and medical advice, the Prince and the Duchess are now self-isolating at home in Scotland.
"The tests were carried out by the NHS in Aberdeenshire where they met the criteria required for testing.
"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."
He last saw the Queen after an investiture ceremony at Buckingham Palace on March 12 and she was in "good health" on Wednesday, a spokesperson said.
The 93-year-old monarch left her central London residence for Windsor Castle last Thursday, a week earlier than usual for Easter, and is following social distancing guidelines with Prince Philip, 98.
The positive test was carried out by the NHS in Aberdeenshire.
There were fears for the Queen when Clarence House announced that Charles had tested positive.
A Buckingham Palace spokeswoman said: "Her Majesty The Queen remains in good health.