A future king is one of a growing number of international celebrities who's in self-isolation.

That's because Prince Charles, the 71-year-old heir to the British throne, has tested positive for the novel coronavirus.

He's reportedly showing mild symptoms as he avoids others in Balmoral Castle in Scotland.

His wife Camilla, the Duchess of Cornwall, has not tested positive.

Clarence House has issued a statement, saying: "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." 

Prince Charles has not seen his mother, Queen Elizabeth, in nearly two weeks.

She's in good health.

Other celebrities who've tested positive for COVID-19 include actor Tom Hanks and his actor-musician wife, Rita Wilson; actor Idris Elba and his Canadian wife, Sabrina Dhowre; former movie mogul Harvey Weinstein; model Olga Kurylenko; Game of Thrones star Kristofer Hivju and his wife, Gry Molvær Hivju; and Hawaii Five-O actor Daniel Dae Kim.