London, UK - Still no sigh of relief for royal fans: Prince Philip remains in a London hospital three days after his admission.

He will rest there for a few days under observation, Buckingham Palace said of the Queen's 99-year-old husband, who was admitted to the hospital on Tuesday.

According to media reports, Prince Philip's stay will continue for a few more days. Insider sources say his ailment is not related to the coronavirus.

Queen Elizabeth II (94) and her husband both received their coronavirus vaccinations in January.

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The Palace described the stay as a precautionary measure.

During the week, the Queen held her usual appointments. She even held a face-to-face event at Windsor Castle, where she awarded her Master of the Household Tony Johnstone-Burt the honorary title of Knight Commander of the Royal Victorian Order.

Prince Philip was treated in the same hospital for a few days at the end of 2019 for a pre-existing condition, but was released again on Christmas Eve – just in time for the holidays.

He has also been treated several times in previous years for various ailments, including a bladder infection, abdominal surgery, and a heart condition, but he always recovered.