The 98-year-old has been taken to the hospital as a precaution for the treatment of an existing condition.
The Duke of Edinburgh has been admitted to the King Edward VII Hospital in London where he will remain under observation for a few days.
Prince Phillip is said to have walked into the hospital unaided and sources say this is part of a planned visit rather than a sudden admission.
This comes as the Queen arrived at Sandringham, where members of the royal family gather for Christmas every year.
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