Doctor Who Spyfall Part One, was watched by an average of 4.88 million viewers, 21.6% of the total TV audience at the time.
The audience is slightly lower than last year's New Year Special which had an overnight figure of 5.15 million watching.
Doctor Who was the second-highest-rated show for the day with Emmerdale taking top honours with 5 million watching. Coronation Street was third, just behind Doctor Who. The new Steven Moffat series Dracula had 3.57 million watching.
The rating does not include those recording the programme and watching it later. Final ratings will be released in two weeks time which are likely to put Doctor Who as the top-rated show of the day.