The Queen is being monitored after a 'recent' meeting with Prince Charles, who tested positive for Covid today.
A Buckingham Palace source told the Mirror that the Queen isn't showing any symptoms, but did "recently" meet with her son.
The Palace has, however, refused to confirm or deny whether Her Majesty has Covid.
The source said the situation will be kept under close observation, but there wouldn't be a running commentary on the 95-year-old monarch's health.
The Queen was given her first Covid vaccine in January 2021 and is believed to have had her second dose last March.
It's likely she's also had a booster jab.
In a tweet earlier today, Clarence House revealed that the 73-year-old prince had tested positive for the virus this morning and as result would be cancelling engagements in Winchester today.
The tweet by Clarence House said: "This morning The Prince of Wales has tested positive for COVID-19 and is now self-isolating.
"HRH is deeply disappointed not to be able to attend today's events in Winchester and will look to reschedule his visit as soon as possible."
He and Camilla attended a black tie event held by the British Asian Trust at the British Museum last night and met scores of people.
Meanwhile it has been a historic week for the Queen, who celebrated the 70th anniversary of her accession to the throne on Sunday.
She spent the day at Sandringham, although travelled back to Windsor on Monday, where it is believed she was resuming royal duties.
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