“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.
The announcement comes just days after Philip, 96, was absent from the royal family's Easter service attended by Queen Elizabeth and other royals.
Philip was also due to attend the annual Maundy Service last Thursday at St. George's Chapel Chapel with Queen Elizabeth but cancelled at the last minute due to a problem with his hip.
Philip's condition at the time was thought to not be serious. He was spotted driving on the Windsor Castle grounds as recently as last week, according to the U.K.’s Press Association.
The Duke of Edinburgh retired from royal duties last summer but still makes appearances with the royal family.
At the time of his retirement, Philip had completed 22,219 solo engagements since 1952, gave 5,496 speeches in his travels to more than 76 countries, authored 14 books, served as patron to 785 organizations and made 637 solo overseas visits, Buckingham Palace said.
In his customary good humor, Philip joked to a well-wisher who said he was sorry the duke of Edinburgh was standing down shortly after the retirement announcement by responding, “Standing down? I can barely stand up these days.”
Philip's last hospitalization was in June 2017 when Buckingham Palace was forced to announce he had been hospitalized because he was going to miss the State opening of Parliament he attended annually with Queen Elizabeth.
"The Duke of Edinburgh was admitted to King Edward VII Hospital in London last night, as a precautionary measure, for treatment of an infection arising from a pre-existing condition," a Buckingham Palace spokesman said at the time.
Philip has had a number of hospitalizations in the last 10 years.
During Queen Elizabeth's Diamond Jubilee celebrations in June 2012, he was hospitalized for a bladder infection just before his 91st birthday. Buckingham Palace announced in August he was readmitted to the hospital while on his annual Scottish summer at Balmoral.
In 2013, the royal household said Philip had once again been admitted to the hospital for exploratory surgery after his doctors revealed that it was necessary following “abdominal investigations." The surgery was conducted under general anesthetic and the palace later said he was progressing satisfactorily but would remain in the hospital for approximately two weeks.
In December 2011, the prince suffered chest pains and had minor surgery to open a blocked artery.
In October 2007, it was revealed that the prince had been suffering from a heart condition since 1992. In April 2008, he was hospitalized for a chest infection, but recovered quickly.
Philip is currently expected to attend Harry and Markle's May 19 wedding at St. George's Chapel with other members of the royal family.