"His Royal Highness The Duke of Edinburgh was admitted to King Edward VII Hospital in London this afternoon, for planned surgery on his hip which will take place tomorrow", Buckingham Palace said in a statement.
Prince Philip is recovering in a London hospital following hip replacement surgery.
He also did not attend two other recent events at Windsor Castle - the Royal Maundy Service at St George's Chapel on 29 March, and a parade on 22 March to mark Prince Andrew's appointment as Colonel of the Grenadier Guards.
Philip was an avid sportsman for many years and saw active duty in the Royal Navy during World War II.
Philip underwent a full replacement, considered a major procedure by medics, according to the NHS.
His final solo engagement was in August previous year, when he reviewed a parade of Royal Marines outside Buckingham Palace in his capacity as Captain General of the corps. The palace later said that he was progressing satisfactorily after the surgery, but had to remain in the hospital for approximately two weeks.
The Duke of Edinburgh pictured at King's Lynn railway station.
The announcement comes just days after Philip, 96, was absent from the royal family's Easter service attended by Queen Elizabeth and other royals.
Officials declined to provide additional details about the surgery and said "further updates will be issued when appropriate". "That's more important than someone's chronological age".
In June 2017, the 96-year-old prince was admitted to the private King Edward VII Hospital as "a precautionary measure" following an infection derived from a pre-existing condition.
Modern artificial hip joints are created to last for at least 15 years, with the majority of recipients experiencing a significant reduction in pain and improvement in movement.
Philip is now expected to attend Harry and Markle's May 19 wedding at St. George's Chapel with other members of the royal family.
Philip has been in generally good health for his age, but he was briefly hospitalised over Christmas in 2011 for angioplasty treatment of a blockage in his coronary arteries.