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.


Trump says 'a whole civilisation will die tonight' if Iran does not make a deal
One attacker dead, two injured in gunfight outside Israeli consulate in Istanbul
French high speed train crashes into military truck, killing driver
Israeli military tells people in Iran to avoid using trains
Three killed after Russian drone hits city bus in Ukraine's Dnipro region