The episode, which starred Kylie Minogue as a waitress on-board a doomed spaceship named 'The Titanic', peaked with a massive 13.8 million viewers and a 55% share of the TV audience.
Overall, Doctor Who averaged 12.2 million viewers across its 70 minutes to rank as the second most-watched programme of Christmas Day.
The figures are the highest achieved by the cult show since 1979. The previous best for the new series was 10.8 million for its 2005 rebirth episode, 'Rose'.
> Click here for the Christmas Day ratings in full