Camilla, Duchess of Cornwall has tested positive for COVID-19 four days after her husband Prince Charles was confirmed to be infected with the coronavirus, the couple’s office said Monday.

READ MORE: Prince Charles Isolating After Testing Positive For COVID-19

Clarence House said Camilla was self-isolating. Charles has been isolating since he tested positive on Thursday, but Camilla had continued with public engagements while taking daily tests.

Both Charles, 73, and 74-year-old Camilla are triple-vaccinated.

Charles, who is heir to the British throne, previously contracted the coronavirus in March 2020, during the first wave of the pandemic.

READ MORE: The Queen’s Being Monitored But Isn’t Displaying Any Symptoms Following Prince Charles’ COVID-19 Diagnosis

Charles is believed to have met with his mother Queen Elizabeth II early last week when both were at Windsor Castle. Buckingham Palace hasn’t said whether the 95-year-old queen has tested positive, though it said last week she wasn’t displaying symptoms.