The Queen and other members of the royal family have visited the Duke of Edinburgh in hospital, where he is recuperating following treatment for a blocked coronary artery.
The Earl of Wessex, the Princess Royal and the Duke of York accompanied the Queen as they visited Philip's bedside at Papworth Hospital, Cambridge.
The Duke, 90, was "in good spirits", Buckingham Palace said. The Palace had earlier said Philip had spent a "good night" following the coronary stent procedure yesterday evening.
The Duke is expected to wake up in hospital on Christmas morning.
The Palace said: "The Queen, the Duke of York, the Earl of Wessex and the Princess Royal arrived from Sandringham to Papworth by helicopter before 11am.
"They were met by Mr Stephen Bridge, chief executive of Papworth, and Professor John Cunningham, physician to the Queen. The visit lasted 45 minutes. Prince Philip is in good spirits.
"The Prince of Wales and Duchess of Cornwall also arrived by car 45 minutes later."
There were no further details about when the Duke would be discharged.
The Queen was flown in to Papworth this morning from Sandringham, her private Norfolk estate, where the royal family is spending Christmas.
The royal helicopter touched down near the hospital and the visitors were driven in in a convoy of two Range Rovers and a third car.
The royal party returned to the helicopter and was flown away shortly before midday.
Philip was taken to the specialist heart hospital last night after complaining of chest pains, and following tests a blocked artery was discovered by doctors.
He underwent an "invasive procedure of coronary stenting", which was declared a success.
It is not known when he will be discharged, but medical experts have said that many patients can leave hospital a day after undergoing the procedure, providing there are no complications.
Speaking outside the hospital, Ailsa Anderson, a spokeswoman for Buckingham Palace, said: "The Duke of Edinburgh had a good night and is in good spirits but he is eager to leave.
"Tomorrow's church service is going ahead as planned and we don't anticipate changes to the Royal Family's Christmas celebrations."
The Palace said there will be no further statements from the family today.
The Queen will remain briefed and Philip will remain under observation for a "short period" but it is not thought he will be discharged today.
Philip would normally have been welcoming guests to Sandringham, the Queen's private home, which is set in 60 acres of gardens, offering the perfect sanctuary for the family's break.
But if he makes good progress he could be back among them for the Boxing Day shoot, which he was reportedly supposed to be leading.
Christmas Eve is an important day for the royals as they follow the German tradition of opening their presents then - something Queen Victoria and Prince Albert did.
Papworth describes itself as the UK's largest specialist cardiothoracic hospital and the country's main heart and lung transplant centre.
Dr Simon Davies, consultant intervention cardiologist at the Royal Brompton Hospital in London, said Philip may have been on the verge of a heart attack or could actually have suffered one before the stenting procedure was performed.
Dr Davies said: "What they have done is they put a miniature sausage-shaped balloon down the artery, pushed the balloon into the narrowed section and then blown it up.Suggest a correction