WARNING!!! SPOILERS MAY FOLLOW:

1. Guest cast including Claire Skinner (Outnumbered), Bill Bailey (Black Books), Arabella Weir (The Fast Show) and Alexander Armstrong (Armstrong & Miller), join Matt Smith in the emotional festive special, packed full of Christmas thrills and chills.
2. the Doctor (Matt Smith) finds himself in war-torn England embarking on a magical and mysterious adventure with a young widow and her two children.
3. Steven Moffat: "The Doctor at Christmas - nothing is more fun to write. Maybe because it's so his kind of day - everything's bright and shiny, everybody's having a laugh, and nobody minds if you wear a really stupid hat. Of all the Doctors, Matt Smith's is the one that was born for this time of year - so it's the best news possible that he's heading back down the chimney."
4. The special, set during World War II, sees Madge Arwell and her two children, Lily and Cyril, evacuated to a draughty old house in Dorset, where the caretaker is a mysterious young man in bow tie, and a big blue parcel is waiting for them under the tree. They are about to enter a magical new world and learn that a Time Lord never forgets his debts...