The 99-year-old Duke of Edinburgh, Prince Philip, was taken to the King Edward VII Hospital Tuesday night as a precautionary measure after he expressed not feeling well.

Queen Elizabeth’s husband’s diagnosis hasn’t been announced as of Wednesday, but it’s been reported by a royal source that his hospitalization isn’t COVID-19 related. The couple received the first doses of the vaccine in January and are awaiting their second doses.

"The Duke's admission is a precautionary measure, on the advice of His Royal Highness's Doctor, after feeling unwell. The Duke is expected to remain in the hospital for a few days of observation and rest," The Buckingham Palace press release stated.

Social media users have been sending their condolences and best wishes to Prince Philip and the rest of the family since the news broke.

The Duke retired from all royal duties and stepped out of the limelight in 2017, CNN reported.

The Queen and Prince have been spending most of the COVID-19 pandemic in Windsor Castle and have kept to themselves to reduce the chances of contracting the virus, which has been considered more likely to cause serious illness in those who are aged 85 or older. They even spent most holidays away from the rest of their family.

The queen and her 99-year-old husband Prince Philip are in line to get the jab early due to their age
The queen and her 99-year-old husband Prince Philip are in line to get the jab early due to their age AFP / Adrian DENNIS