The Queen made her first Christmas broadcast in 1952
The Queen and other members of the Royal Family have attended a church on the Sandringham estate, in Norfolk, for a Christmas Day service.
The monarch, Prince Philip and a number of royals attended the service at St Mary Magdalene Church before returning to Sandringham House for lunch.
The Queen's Christmas message will be broadcast at 1500 GMT.
She is expected to pay tribute to the armed forces in Afghanistan and urge more discussion about the environment.
This year more than 100 UK servicemen were killed in Afghanistan and world leaders met to discuss climate change.
The annual speech usually has a strong religious framework, reflects current issues and often draws on the Queen's own experiences and concerns.
The armed forces and the Commonwealth are known to be two areas of close interest for the 83-year-old monarch.
And the environment is an issue that has been high on the Commonwealth's agenda.
She will say in her speech: "It is important to keep discussing issues that concern us all - there can be no more valuable role for our family of nations."
At a gathering of leaders from the institution's member states last month, the Queen urged them to take a lead in the international response to the challenge of climate change.
About 500 onlookers watched the royals arrive for the service, led by Sandringham rector Jonathan Riviere, and security was tight.
The Queen was joined by the Prince of Wales, the Duchess of Cornwall and Princes William and Harry, among others.
Most of the royal party, including the Duke of Edinburgh, walked the quarter mile route from Sandringham House to the church along an icy path.
The Queen and Royal Family leave church following a service
Police searched visitors and more than a dozen officers monitored crowds lining the path the royals walked along.
The Princess Royal, the Duke of York and his daughters Princesses Beatrice and Eugenie, and the Earl and Countess of Wessex are also among the attendees.
After the service, children lined up to give the Queen flowers, which she passed to police officers who took them to her car.
Other royals exchanged festive greetings with onlookers as they walked back to Sandringham House.
Princes William and Harry are both on leave from their military training as helicopter pilots.
The Royal Family are rarely all together under one roof and, as with many families, Christmas is the one occasion during the year when they all come and stay with each other for a few nights.
After lunch it will be time for the Queen's Christmas broadcast, which was recorded earlier this month at Buckingham Palace.
With the losses suffered by the armed forces in Afghanistan on many people's minds this Christmas, the Queen is expected to take the opportunity to re-state her admiration for the work that Britain's servicemen and women are doing there.
The Queen's Speech will be broadcast on BBC One at 1500 GMT on Christmas Day, and shown again at 1850 GMT on BBC Two.
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