According to Buckingham Palace, the Duke of Edinburgh was admitted to The London Clinic on Harley Street, one of the UK's largest private hospitals, last night shortly after he attended a palace garden party yesterday afternoon.
"His Royal Highness, the Duke of Edinburgh, has been admitted to the London Clinic for an exploratory operation following abdominal investigations. He is expected to stay in hospital for up to two weeks. Further updates will be issued when appropriate," a palace spokesperson said.
A spokesperson at the clinic described the Duke, who turns 92 on Monday, as being in good spirits.
It is the fourth time in two years that Prince Philip has been hospitalised, raising concerns about his health.
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Experts suggest the latest surgery could either involve a laparoscopy, a form of keyhole surgery, or a laparotomy.
British Prime Minister David Cameron's office sent a message to the prince on Twitter, saying, "The prime minister wishes the Duke of Edinburgh a swift recovery."
On Monday, he had pulled out of an engagement for the Royal National Institute of Blind People after becoming unwell ahead of last week's service marking 60 years since the Queen's coronation.
Meanwhile, the 87-year-old queen carried on with her normal schedule of public engagements, which includes the official opening of the BBC's new headquarters at Broadcasting House in central London today.
Prince Philip had been due to join her.
The couple married in 1947 and Philip is the longest-serving royal consort in British history, described by the Queen in 1997 as "my strength and stay all these years".
Despite their age, they both maintain a busy schedule and although the Queen has cut back her long-haul flights this year, the Duke visited Canada in April.
He was moved to England when just 18 months old to attend a preparatory school.
As a Royal Navy cadet, he served on battleships in the Indian Ocean and the Mediterranean during World War II.