The Queen missed the Sunday church service at her Sandringham estate at the weekend after suffering from a cold. The monarch usually visits St Mary Magdalene Church most Sundays while staying at her Norfolk home.
But this weekend she did not attend church to the disappointment of dozens of well wishers who gathered to get a glimpse of her.
A Buckingham Palace spokeswoman said: "The Queen was getting over the tail end of a cold. We are expecting business as usual next week."
The Duke of Edinburgh, 91, walked the few hundred yards from the house to the church accompanied by the Duke of York, the Earl and the Countess of Wessex and their daughter Lady Louise and Princesses Beatrice and Eugenie.
Royal watcher Mary Relph, 78, said that she has waited outside the church to spot the Queen every time the monarch has attended a service since 1988.
"I don't remember her ever missing it," she said.
"I remember her going around the back once. I am disappointed but I hope she is OK."
Speaking before news of the Queen's cold emerged, Michelle Dickinson, 44, from Norwich, added: "I am very disappointed but hope she is all right, I wonder whether she is poorly?
"This is our first time here but we'll come again another time so we can see her."
The Queen traditionally spends the festive period with her family gathered around her at her Norfolk estate. But this year there will be some empty spaces around the table on Christmas Day.
The Duke and Duchess of Cambridge are planning to spend Christmas at the Middleton family home. And Prince Harry is currently serving as an Apache pilot in Afghanistan.
St James's Palace said Prince William and his pregnant wife are to spend the day privately in Bucklebury, Berkshire - a decision taken with the approval of the Queen and the Duke of Edinburgh. But the pair do plan to visit Sandringham at some point over the festive period.
Kayleigh Allen, nine, who was standing in the crowd outside the church, brought a special soft toy labelled My First Toy for the pregnant Duchess.
Last year, hundreds of well-wishers turned out to see the Duchess of Cambridge attend her first Christmas Day service at church in Sandringham. But the Duke of Edinburgh missed the celebrations and instead spent four days at Papworth Hospital, in Cambridgeshire, following a procedure to clear a blocked artery.
The Duchess's return to the bosom of her family comes after a testing few weeks for Kate who was forced to announce her pregnancy earlier than planned when she was admitted to hospital following a bout of severe morning sickness. The Duchess left King Edward VII's Hospital in London on December 6, following treatment for a condition known as hyperemesis gravidarum, which leaves expectant mothers so ill they cannot keep food or liquids down.