Prince Charles, who has tested positive for COVID-19 for a second time, recently met his mother the Queen, a palace source has said.
Charles, 73, pulled out of an event to mark the Queen's Platinum Jubilee overnight after receiving news of his positive test..
"This morning The Prince of Wales has tested positive for COVID-19 and is now self-isolating," his office, Clarence House, said in a statement on Twitter.
There was no immediate comment on his condition but a Buckingham Palace source confirmed he had recently met his 95-year-old mother.
The BBC reported the meeting between the pair happened on Tuesday at Windsor Castle, where the Queen has been residing since the beginning of the pandemic.
The Queen was not displaying any symptoms, but the situation was being monitored, the source said.
In early 2021 the Queen confirmed she had received her first COVID vaccine dose, encouraging others to also have the shot, but the palace has declined to confirm whether she has received subsequent shots, saying it does not comment on private medical matters.
Charles confirmed in December that both he and his wife, Camilla, had received their booster shots.
The health of the Queen, the world's oldest and longest-reigning monarch, has been in the spotlight since she spent a night in hospital last October for an unspecified ailment and then was advised by her doctors to rest.
On Monday, a day after she celebrated seven decades on the throne, a palace source said she was intending to return to normal duties, with a number of public appearances planned for next month.
Camilla went ahead with engagements in London on Thursday and has tested negative.
On Wednesday Prince Charles attended a reception for the British Asian Trust where pictures showed him chatting to other guests including Chancellor of the Exchequer Rishi Sunak and Home Secretary Priti Patel.
A spokesperson for Mr Sunak said the minister had tested negative for COVID.
Second COVID-19 infection for Charles
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.
During her engagements on Thursday, Camilla said she was "very, very honoured" and "very touched" by the Queen publicly stating her desire that she become Queen Consort when Charles becomes King.
Camilla, Charles's second wife, was vilified by the tabloid media after the breakdown of Charles's first marriage to the late Princess Diana, and after her death in 1997.
Coverage has become much more sympathetic in recent years and a poll for the Daily Mail on Wednesday suggested that 55 per cent of the British public now supported her becoming Queen Consort compared to 28 per cent who were opposed.
However, other surveys have indicated that many people still remain hostile to her taking the title, with a YouGov poll in November finding just 14 per cent backed her being Queen.
ABC/Reuters