Some four million people watched Downton Abbey's Christmas special, which was partly filmed in Alnwick, in the week following its broadcast - the biggest 'catch-up' audience for any UK TV programme on record.
The figure means Downton's festive farewell was enjoyed by a total of 10.92million people, enough to make it one of the top 40 most-watched programmes of 2015. Before the catch-up figures were added, the audience stood at 6.9million.
It it also the second-highest audience for any Downton Abbey Christmas special and a big jump on last year's final figure of 7.66million, after 5.8million watched on the night.
This is another boost for the Northumberland town, which played a key role in the Yuletide offering for the second year running. Business leaders will hope to reap benefits from fans visiting the settings of the last-ever episode in the popular period drama.
Jude Leitch, director of Northumberland Tourism, said: "Exposure such as this is invaluable for tourism in Northumberland and contributes significantly to the £765m tourists spend each year. Despite the wonderful landscapes, history and culture so familiar to our residents and regular visitors, the county is still relatively unknown as a tourism destination.
"Without the resources for high-profile campaigns, we take every chance to gain attention, and programmes and movies such as Downton Abbey, Harry Potter, Robson Green’s Tales from Northumberland (which is about to return for its third series), Beowulf and Vera provide money-can’t-buy opportunities, not only to reach significant audiences within Britain but also internationally.
"We at Northumberland Tourism, in partnership with Active Northumberland, make every effort to encourage and assist production companies and film crews and we hope that Northumberland will continue to star in many more productions in future."
Other programmes did less well, however, with both EastEnders and Coronation Street failing to get enough of a boost from catch-up audiences to jump up the Christmas Day chart.
The new figures have been published by the Broadcasters' Audience Research Board (Barb).
They show that while ITV's Downton Abbey was the most-watched show on Christmas Day, BBC1 dominated the rest of the top 10. Mrs Brown's Boys came second with 9.49million viewers, down a little from 9.69million in 2014, when it took first place.
Call the Midwife was third with 9.30million, Stick Man was fourth with 9.28million and Strictly Come Dancing fifth with 8.54million. The Queen's Christmas message was broadcast simultaneously on BBC1 and ITV and had a combined audience of 7.76million.
The rest of the top 10 was made up of Doctor Who, EastEnders, Coronation Street and the film Brave. Doctor Who's ratings were 7.69million: the lowest for any Christmas special to date. Soaps underperformed by historical standards, with EastEnders managing just 7.67million - a far cry from the 16.97million it won on Christmas Day 2002. Coronation Street attracted 7.28million viewers, roughly half the number it had in 2002 (14.18million).
The figures also suggest that Christmas Day audiences overall are in long-term decline. Between 2000 and 2005, 23 programmes broadcast on December 25 were watched by at least 10million people. In 2006-2010, this slipped slightly to 21. But between 2011 and 2015, the number fell to just eight programmes topping 10million viewers.
Final Christmas Day viewing figures
1. Downton Abbey (ITV) 10.92million
2. Mrs Brown's Boys (BBC1) 9.49million
3. Call the Midwife (BBC1) 9.30million
4. Stick Man (BBC1) 9.28million
5. Strictly Come Dancing (BBC1) 8.54million
6. Queen's Christmas message (BBC1 and ITV combined) 7.76million
7. Doctor Who (BBC1) 7.69million
8. EastEnders (BBC1) 7.67million
9. Coronation Street (ITV) 7.28million
10. Film: Brave (BBC1) 6.05million