Prince Philip, 96, has been admitted to hospital for planned surgery on his hip.
The Duke of Edinburgh has travelled to the King Edward VII Hospital in London ahead of the operation tomorrow, Buckingham Palace said.
It comes days after he pulled out of the traditional Easter Sunday and Maundy services at Windsor Castle over the weekend.
The Prince’s hip is believed to have been bothering him for around a month and it is understood the operation will happen under general anaesthetic.
Speaking today, Buckingham Palace said: “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.
“Further updates will be issued when appropriate.”
Scarlett McNally, Council member of the Royal College of Surgeons and an orthopaedic surgeon said the risks of surgery usually come down to a person’s fitness than their age.
She said: “All operations may have complications and some patients are at greater risk.
“A person’s fitness is more important than their chronological age.
“Surgeons will always take account of these risks in helping patients decide whether they wish to proceed with surgery.”
She added: “Hip surgery is very effective at relieving pain and improving mobility, including in older patients.
“A whole team is involved including anaesthetists and physiotherapists.
“Performing it on higher risk patients still provides great benefit for the majority.”
Philip was spotted carriage riding in Windsor last Wednesday but since then missed public events due to the problem with his hip.
Among them was a Maundy Thursday event last week and he was also not among the congregation as the royals headed to St George’s Chapel on Sunday morning – the same venue where Prince Harry will wed
Meghan Markle next month on May 19.
He was named in the order of service for the event on Sunday.
A palace spokeswoman said on Sunday: “The order of service was printed some weeks ago when it was hoped the Duke would be able to take part.
“His Royal Highness has since decided not to attend.”
The duke stepped down from his public duties last summer but on occasion does attend events with the Queen.
When it was announced last year that he would be retiring from official engagements, Buckingham Palace stressed that the decision was not health-related and he had the full support of the Queen.
His final royal engagement was in August, where he attended a parade of Royal Marines and met servicemen who have taken part in a 1,664 mile race to raise money for the Royal Marines Charity.
One of the last times Philip was seen recently was attending St Peter and Paul Church in West Newton, Norfolk, for a Sunday morning service in February.
Prince Charles and the Duchess of Cornwall, who often spend Easter at Birkhall, their Highland retreat on the Balmoral estate, were also not there.
They left Heathrow for Singapore on a scheduled Singapore Airlines flight last night.
The royal couple are due to open the Commonwealth Games in Brisbane, Australia, on April 4 and are due to be collected from Singapore by an Australian military plane.
It was a case of battle of the bumps as Kate and Zara made their appearances at St George’s Chapel for the service on Sunday as they prepare to welcome the new royal additions.
Prince William and Kate arrived after the monarch had led the family into the church amid speculation they were held up travelling from Kate’s parents home in Berkshire.
Kensington Palace declined to comment on why the Cambridges were late. Their children, Prince George, four, and Princess Charlotte, two, did not attend the hour-long service.
The appearance could be Kate’s last before she gives birth to her third child, due later this month.
Prince Phillip announced in May he was stepping down from public duties after wrapping up his commitments through to August.
The move came after he has faced numerous health battles over the past few years.
The Duke was taken to hospital by helicopter from Sandringham after suffering chest pains in December 2011.
The in 2012 he was forced to miss the majority of the Queen’s Diamond Jubilee celebrations due to a bladder infection.
It came back in August of that year, leading to him spending five nights at the Aberdeen Royal Infirmary.
In June 2013, he was admitted to hospital for an exploratory operation on his abdomen.
In May 2014 he had an operation on his right hand inside Buckingham Palace and was seen wearing a bandage to protect it. That June he spent his 92nd birthday in hospital and left after 11 nights.