The PBS show "Downton Abbey" appears to have some cast changes in store, as a fan favorite has reportedly said she wants out, according to the U.K.’s Daily Mail. (Warning: This story may contain spoilers.)

Dame Maggie Smith has told writer Julian Fellowes that she wants the third season to be her last, the story reports. The third season, which is currently being filmed on location and in studios in London, will return to British airwaves in September, the piece notes.

Fellowes is preparing to write out Smith’s character, the acerbic Dowager Countess, who delights in delivering putdowns to the show’s other characters. The Dowager Countess will reportedly be struck by a fatal illness toward the end of the third series, the piece says.

Smith has agreed to work on a "Downton Abbey" Christmas special, the story notes. Her reason for wanting to end her work on the series is so that she can pursue other roles, the piece adds.

Smith, 77, won an Oscar for her work in the 1969 movie "The Prime of Miss Jean Brodie," although she’s probably better known for her role as Professor McGonagall in the "Harry Potter" films.

Here’s a collection of Dowager Countess clips from the show …