One of the biggest Royal gatherings in recent years will get under way at Sandringham today.
The Queen and Duke of Edinburgh, who arrived in Norfolk by train last week, will be joined by more than 20 family members.
They include little Prince George, who could be spending his first Christmas with both sets of grandparents.
Reports have claimed the Queen has invited Michael and Carole Middleton – the Duchess of Cambridge's parents – to Sandringham for the festive break, although there has been no official confirmation.
The Monarch and other family members traditionally spend Christmas at her private retreat, near King's Lynn.
Also expected to join this year's gathering are Prince Charles and the Duchess of Cornwall, the Princess Royal and Vice Admiral Sir Timothy Laurence, the Duke of York and Princesses Beatrice and Eugenie, the Earl and Countess of Wessex, Lady Louise and Viscount Severn, Zara Phillips and Mike Tindall, and Prince Harry.
Viscount Linley, his wife Serena and their children Charles and Margarita; Lady Sarah Chatto, her husband Daniel and children Samuel and Arthur have also reportedly been invited.
The Queen normally arrives in mid December, to supervise preparations at the house, which include choosing a tree from her sawmills.
Christmas trees became popular around the world in the 1840s, after Queen Victoria and her German-born husband Prince Albert put one up at Windsor Castle.
The following year, illustrations showing the ornament appeared in fashionable London magazines, and millions adopted the tree as the centrepiece of their celebrations.
Most family members will arrive today, in time for tea at 4pm sharp. In previous years, Prince William has joined a traditional Christmas Eve football match during the afternoon between Sandringham estate workers and villagers from neighbouring Castle Rising.
This evening, family members will open their presents, which are arranged on trestle tables in the Ballroom, before a candlelit supper.
Tomorrow thousands of well-wishers are expected to queue to greet them outside the tiny church of St Mary Magdalen, close to Sandringham House.
December 25 is normally the only day of the year on which senior members of the Royal Family are seen together in the same place.
Most walk the short distance to the church from the house, led by the Prince Philip.
Bumper crowds are expected to attend this year in the hope of catching a glimpse of Prince George, now three months old, on what may be the first time he is seen in Norfolk.
His parents may decide to keep the baby heir in the warm at the house and not bring him to the service.
Children line up with flowers to present the Queen with flowers and presents after the service, which is broadcast to the crowd outside the church via a PA system.
After church, the family sit down to a Norfolk turkey, with all the trimmings, before they watch the Queen's Speech. The monarch's address to the nation was a tradition which began in Norfolk, in 1932, when the Queen's grandfather, King George V, took to the then new-fangled medium of the wireless to address the Commonwealth.
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