"The Duke of Edinburgh travelled from Norfolk this morning to the King Edward VII Hospital in London for observation and treatment in relation to a pre-existing condition," read a statement from the palace.
"The admission is a precautionary measure, on the advice of His Royal Highness' Doctor."
With her husband in hospital, Queen Elizabeth attended church in Sandringham on Sunday, December 22, with her daughter-in-law Sophie, Countess of Wessex.
Her Majesty wore a dark green outfit with a matching hat and brooch for the Sunday service, which was also attended by her youngest son, Prince Edward, and his children, Lady Louise Windsor and James, Viscount Severn.
It's thought that the Wessexes will remain in Norfolk for the next few days, spending Christmas Day at Sandringham House with The Queen, Philip and other senior royals.
Though concern was mounting for the Prince's welfare with each day he spent in hospital, he was reportedly in good spirits and had been laughing and joking with hospital staff.
"The Duke has had a bad turn recently and has been looking much frailer of late," one source told Daily Mail.
"He's a remarkable man who has always prided himself on how robust he is, but he is six months off his 99th birthday and age takes its toll."
With Philip home in time for Christmas Day, the palace is no doubt breathing a sigh of relief. After all, Queen Elizabeth had to cancel some of the family's other annual traditional holiday activities due to his illness.
According to Express, the Queen chose to cancel a family pheasant shoot, which was supposed to take place on Saturday – despite it being at the height of shooting season. While Philip no longer participates in the shoot, it’s understood he liked to watch the action from a distance, so it’s thought the Queen may have cancelled the event out of respect for him.
However, the royals did still take part in the recent pudding-making cook-off, which provides support to the Armed Forces and veteran communities.
Little Prince George joined four generations of the royal family – including his great grandmother the Queen, his father Prince William and his grandfather Prince Charles – to help mix the batter for puddings, which form part of 99 puddings distributed across the charity’s network in the UK and the Commonwealth to mark The Royal British Legion’s 99th year.
