Camilla, the wife of British heir-to-the-throne Prince Charles, has tested positive for coronavirus.

"Her Royal Highness The Duchess of Cornwall has tested positive for COVID-19 and is self-isolating," Clarence House said in a statement. "We continue to follow government guidelines."

The 73-year-old Charles tested positive for COVID-19 for a second time last week. Clarence House have not given an update on his condition and it did not give any further details about Camilla on Monday.

Both Charles and Camilla had been fully vaccinated against COVID-19, including a booster shot.

A royal source told Reuters last week that Charles had met his mother Queen Elizabeth two days before his positive test. The source said at the time that the monarch was not displaying any symptoms, but the situation was being monitored.

Charles previously tested positive for the virus in March 2020 when he said he had been "lucky" to have suffered only mild symptoms. His son Prince William also contracted COVID shortly after his father in 2020.