A dozen television news crews headed to Buckingham Palace in the early morning, and the website of one tabloid reported, in an article that was quickly taken down, that the prince had died.
The Duke of Edinburgh has suffered from heart disease and other illnesses over recent years but has always maintained a rigorous schedule.
Officials said the queen, who turned 91 last month, will carry on her royal engagements with the support of the royal family.
Before he married Queen Elizabeth II, Prince Philip - born into Greek and Danish royal families - became a member of the Royal Navy after he was educated in France, Germany and the U.K. That explains why through the years he sometimes wore official military dress for certain events.
In a message from Downing Street, British Prime Minister Theresa May said she wanted to offer the country's "deepest gratitude and good wishes" to the Duke of Edinburgh following today's announcement.
Prince Philip is patron, president or a member of over 780 organisations, the statement added, noting he'd "continue to be associated" with the groups "although he will no longer play an active role by attending engagements".
"Her Majesty will continue to carry out a full programme of official engagements with the support of members of the royal family", the palace stressed.
The meeting was called somewhat last minute, leading many to fear that some actual emergency was taking place at the palace.
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Prince Philip may have chose to step down from his public role as he approaches his 96th birthday, but he apparently has no intention to retire his famous one-liners.
Queen Elizabeth and Prince Philip on their wedding day in 1947.
Prince Philip has been ever present at his wife's side since she took the throne in 1952.
The queen is normally quite reserved about her private life, but she broke with tradition in a 1997 speech marking their 50 years of marriage.
The royal statement may have put her husband's future plans front and centre, but there were also clear messages from the monarch about what this will mean for her going forward.
The fact that staff from all the royal households were called to the meeting at Buckingham Palace to hear the announcement is telling in itself.
Inspite of being at the forefront of the royal family for nearly 70 years and also patron, president or a member of more than 780 organisations, he has no clear-cut constitutional role and has admitted struggling to carve out a role for himself as the queen's consort.