There is no end in sight to the upstairs-downstairs drama of "Downton Abbey."

Britain's ITV network says it has commissioned a sixth season of the popular costume drama from co-producers Carnival Films and Masterpiece. It will start filming early next year.

ITV's director of drama commissioning, Steve November, said Thursday that the show continues to be "a phenomenon."

He said the network doesn't know yet what series writer Julian Fellowes has planned for his much-loved characters.

The Emmy Award-winning show follows the fates of the aristocratic Crawley clan and their servants amid the social upheavals of the 1910s and 1920s.

The fifth series of "Downton Abbey" is currently airing in Britain and starts Jan. 4 on PBS in the United States.