The period drama, which is set in the U.K., just completed its fifth season in the U.S.

Smith recently told the London Times, "They say this is the last [season], and I can’t see how it could go on…I mean, I certainly can’t keep going. To my knowledge, I must be 110 by now. We’re into the late 1920s." A spokesperson for Milk Publicity, however, told The Associated Press that Smith previously agreed to stay with the series "for as long as the show runs." 

No announcement has been made about a seventh season of the series.

Smith, who won a Tony for her performance in Lettice and Lovage, had told the Times she has no plans to retire. The 80-year-old actress explained, "When you’re not working it’s scary, and when you are working it’s scary, because you don’t know if you’ve got the energy to get through the day…But the bleakness of not doing it, and missing out on the friendships that you make, is too much to bear."

Included in her wealth of Broadway, West End, screen and television appearances over the past six decades are The Prime of Miss Jean Brodie, New Faces of 1956, Private Lives, "California Suite" and the role of Professor Minerva McGonagall in the "Harry Potter" films.