Prince Philip is in a London hospital as a "precautionary measure," after being admitted for "feeling unwell."
The 99-year-old husband of Queen Elizabeth II was taken to the King Edward VII Hospital on Tuesday.
The member of Britain's royal family went on the advice of his physician, a Wednesday statement from Buckingham Palace said. The Duke of Edinburgh is "expected to remain in hospital for a few days of observation and rest."
The hospital stay is not said to be related to the coronavirus pandemic. Prince Philip, who marks his 100th birthday in June, received the first dose of the COVID-19 vaccine along with the queen in early January.
The royal family patriarch, who married then-Princess Elizabeth in 1947, is the longest-serving royal consort in the United Kingdom. He retired from his royal duties in 2017.
— Updated at 10:35 a.m.