Prince Philip has been admitted to hospital.
The 98-year-old royal travelled to London from Norfolk on Friday (20.12.19) and was admitted to the King Edward VII Hospital as a "precautionary measure", Buckingham Palace has revealed in a statement.
The statement said: "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. The admission is a precautionary measure, on the advice of His Royal Highness' Doctor."
It is understood that the admission had been planned in advance and the royal was able to walk into the hospital unaided.
He is expected to remain in hospital for a few days.
Philip's admission to hospital comes on the same day as his wife, Queen Elizabeth, left London to travel to her Sandringham estate in Norfolk to begin her Christmas break.
The Queen, 93, caught the 10.45am First Capital Connect service from London King's Cross to King's Lynn station, Norfolk.
She is expected to remain at the estate until after the anniversary of her father's death on 6 February.
In 2017, Prince Philip retired from public life and he now spends much of his time in Norfolk.
It was revealed in 2018 that he battled through a cracked rib during Prince Harry and Duchess Meghan's wedding.
The royal was said to have suffered the injury days before the ceremony after falling in the bath - six weeks after he underwent hip replacement surgery.
A royal insider said at the time: "The Duke is not a fan of showering and prefers to bathe.
"But he's a determined man and nothing was going to stop him attending nor would he take any kind of walking aid."
Philip went under the knife on April 4 2018 at King Edward VII Hospital in central London for his hip replacement and he subsequently spent nine days on bed rest before being allowed to return home.
When he left the medical facility, a spokesperson for Buckingham Palace said in a statement: "His Royal Highness The Duke of Edinburgh left King Edward VII's Hospital at midday today following a hip replacement operation last week.
"The Duke will continue his recovery at Windsor. His Royal Highness would like to convey his appreciation for the messages of good wishes he has received."
A source said at the time: "The duke is already walking unaided. He has amazing willpower. When he sets his mind to something he gets on and does it.
"He has been walking up and down stairs several times in succession.
"He has also been charging across rooms at full speed. He even had to be told to slow down."