Queen Elizabeth, 95, has tested positive for COVID and is experiencing mild symptoms, Buckingham Palace said on Sunday.
"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."
Charles, 73, the heir to the throne, earlier this month pulled out of an event after contracting coronavirus for a second time. A palace source said he had met the queen just days before.
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.
Elizabeth on Wednesday 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.
Israel is poised to send troops into Rafah, the Gazan city it sees as the last bastion of Hamas, Israeli media reported on Wednesday, saying preparations were under way to evacuate war-displaced Palestinian civilians who have been sheltering there.
Former Japanese Prime Minister Taro Aso, a senior figure in the country's ruling party, met with Donald Trump on Tuesday, becoming the latest US ally seeking to establish ties with the Republican presidential candidate.
Russian missiles damaged residential buildings and injured six people in Ukraine's second-largest city, Kharkiv, early on Wednesday, Governor Oleh Synehubov said on Telegram.
Five migrants died in an attempt to cross the English Channel from France to Britain in an overcrowded small boat on Tuesday, hours after Britain passed a bill to deport asylum seekers to Rwanda in a move to deter the dangerous journeys.
Israel bombarded northern Gaza overnight in some of the heaviest shelling in weeks, causing panic amongst residents and flattening neighbourhoods in an area from which the Israeli army had previously down its troops, residents said on Tuesday.