Queen Elizabeth, the world's longest-reigning monarch, tested positive for COVID-19 on Sunday and is experiencing mild symptoms but expects to continue light duties this week, Buckingham Palace said.

The health of the 95-year-old queen, who has been fully vaccinated against coronavirus, has been under the spotlight since she spent a night in hospital last October for an unspecified ailment and was advised by her doctors to rest.

"The Queen has today tested positive for COVID," the Palace said. "Her Majesty is experiencing mild cold like symptoms but expects to continue light duties at Windsor over the coming week."

"She will continue to receive medical attention and will follow all appropriate guidelines," the Palace said.

Charles, 73, the heir to the throne, earlier this month withdrew from an event after contracting COVID for a second time. A Palace source said he had met the queen days before.

On Wednesday Elizabeth quipped to members of the royal household that she could not move much, as she carried out her first in-person engagement since Charles tested positive.

Elizabeth, the world's oldest monarch, celebrated the 70th anniversary of her accession to the British throne in early February.

She is the first British sovereign to spend seven decades on the throne in a dynasty that traces its origins back almost 1,000 years to Norman King William I and his 1066 conquest of England.

(Writing by Guy Faulconbridge; Editing by Kate Holton and Barbara Lewis)

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Queen Elizabeth II
Britain's Queen Elizabeth speaks during an audience where she met the incoming and outgoing Defence Service Secretaries at Windsor Castle in Windsor, Britain, February 16, 2022. Steve Parsons/Pool via REUTERS Photo: Reuters / POOL