Sherlock was the most-watched programme over the festive season for the second year running.
The BBC1 sleuth show, starring Benedict Cumberbatch as the titular detective, returned for a fourth series on New Year's Day.
Consolidated viewing figures show the 90-minute episode drew an audience of 11.3 million, making it the most-watched show across all channels.
The instalment, entitled The Six Thatchers, had a consolidated audience share of 37.8%.
Sherlock producer Sue Vertue said: "We are absolutely thrilled that over 11 million people tuned in to The Six Thatchers on New Year's Day and over the past week.
"It's a show we love to make so it's fantastic that it's also a show that people seem to want to watch, and we are incredibly grateful to all the fans that support it each series."
Last year, Sherlock: The Abominable Bride topped the festive ratings, with 11.6 million viewers.
Sherlock is written and created by Steven Moffat and Mark Gatiss, inspired by the works of Sir Arthur Conan Doyle.