However, it seemed there was no need to worry, as the move was merely a preventive act.
Prince Philip, 96, was admitted to King Edward VII's Hospital in London on Tuesday night (20Jun17) as a "precautionary measure" after falling ill with an infection stemming from an undisclosed pre-existing condition.
The Prince of Wales took Philip's place at the Queen's side when she went to Westminster to give a speech outlining the Government's programme, and the monarch, who attended Ascot as usual, was kept informed about her consort.
Prince Philip left the private hospital through a backdoor after a two-day stay to convalesce at Windsor.More news: Evergreen Lopez sets up Cilic final at Queen's Club
The senior royal was described as being in "good spirits" during his stay.
Prince Philip, 95-year-old husband of Britain's Queen Elizabeth II, is to step down from public life, Buckingham Palace has announced.
It was announced recently that he will no longer carry out any public engagements from Autumn this year. "In taking this decision, The Duke has the full support of The Queen", the Buckingham Palace previously said in a statement (via CNN). He may also occasionally attend other events.
Philip still attends summer garden parties with the queen, hosting more than 2,000 guests at a time, and has maintained his presence at important ceremonial events, including the Trooping the Color procession earlier this month.