Prince Philip has spent a second night in hospital after undergoing a heart procedure.
The 90-year-old Duke of Edinburgh was airlifted on Friday from the Sandringham estate, where the royals were celebrating Christmas, and taken to hospital for an operation to unblock a coronary artery.
He had a tube-like device called a stent fitted to open up the blocked artery in what Buckingham Palace described as a minimally invasive procedure.
A palace spokesperson said he was in "good spirits" after the Queen and his children visited him in hospital on Saturday.
Prince Charles, Prince Andrew, Prince Edward and Princess Anne joined the Queen at his bedside at Papworth hospital near Cambridge.
"The Duke of Edinburgh had a good night and is in good spirits but he is eager to leave," a Buckingham Palace spokeswoman told reporters outside the hospital on Saturday.
The prince will not attend the traditional Christmas Day church service at St Mary Magdalene Church on the Sandringham estate, the palace announced, and reports suggested he could be kept in hospital for up to five days.
Prince Philip has been in largely good health and joined his wife on an 11-day tour of Australia three months ago, but pulled out of a trip to Italy in October nursing a cold.
The health scare means Prince Philip is likely to miss much of the traditional festivities at Sandringham and may also miss hosting his traditional Boxing Day shoot.
The Christmas morning church service was "going ahead as planned" and the royal family's Christmas plans remained unchanged, the palace said.
The Greek-born prince married then Princess Elizabeth 64 years ago, and has become a national institution almost as much for his often brusque comments as for his support for the monarch.
Meanwhile, the Queen was to stress the importance of family when she delivers her annual televised Christmas Day message.
