Plans have long been rumoured for the massively successful ITV series to hit the big screen, with several cast members expressing interest.
Smith, however, is not so keen.
Speaking at the BFI yesterday at Radio Times’ Television Festival, she said: “They talk about there being a film but who knows. I hope you might tell me if you do know.
“I just think it’s squeezing it dry, do you know what I mean? I don’t know what it could possibly be. It’s too meandering.
“Anyway, that’s not my problem, is it? That’s the Lord’s [Julian Fellowes] problem.”
Nodding towards the Dowager Countess’s possible fate, she added: “I could croak it, and it would just start with the body.”
The 82-year-old has never made any secret of the fact that she didn’t actually watch Downton while it was on-air, and was relieved for it to finish.
Speaking this weekend on the attention it brought her, she said: “It’s ridiculous. I led a perfectly normal life until Downton Abbey.
“I’m not kidding. I would go to theatres, I would go to galleries and things like that on my own.
“And now I can’t. And that’s awful. [Even] the Fulham Road’s dodgy.
“And it’s all through television. I had been working for a very long time before Downton Abbey and life was fine, nobody knew who the hell I was.”
Phyllis Logan recently said of a possible big screen outing: “We’d love to have one last hurrah, but it’d be like herding cats.
“The will is definitely there with everybody involved. So, fingers crossed that we can make it all come about at some stage.”