This is the second time that 73-year-old Prince Charles has caught Covid.
He had already suffered from the virus in March 2020 but recovered quickly.
According to his services, he tested positive on Thursday.
According to information from the Guardian, Charles contracted the virus on Wednesday during a reception at the British Museum in London with his wife Camilla and many other people, including members of the government.
The prince was due to inaugurate a statue of the 13th-century Jewish businesswoman Licoricia later in the day, and said he was “very disappointed” that he could not do so, but the inauguration went ahead.
Last June, the Prince of Wales appeared on British television channel Sky News to talk about his first infection.
“I was lucky and I got through it pretty well.
But I got it, so I can understand what others have been through," he said, adding, "I think especially of those who have lost loved ones and couldn't be with them at that time.
For me, this is the most appalling thing.
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“At his age, he has a risk profile”
His entourage had also expressed his concern.
“I have to admit, at first I was quite worried: at his age, he has a risk profile.
My dad had a lot of chest infections, colds and things like that over the years.
So I said to myself, if anyone can beat that, it's him,” Prince William told the BBC.
At the time, he confined himself with his wife Camilia to his home in Birkhall, Scotland, where he was isolated and treated.
This news comes at an important time, as the United Kingdom prepares to celebrate the Platinum Jubilee of Elizabeth II who this year celebrates 70 years of reign.
The queen returned to Windsor Castle in west London at the start of the week to resume her normal activities after celebrating this anniversary in privacy.