The Queen missed a Sunday church service at her Sandringham estate after suffering from a cold, Buckingham Palace said.
The monarch usually visits St Mary Magdalene Church every Sunday while staying at her Norfolk home. But 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.
The Press Association, photo by Lady Diana Frances