Dame Maggie Smith has said a touted Downton Abbey film risks squeezing the hit period drama series dry.
The actress, 82, starred as the much-loved Dowager Countess in the ITV series until it ended in 2015.
Rumours of a film spin-off have circulated since the finale, with writer Julian Fellowes revealing in January that he had started working on a script.
Speaking at the BFI And Radio Times Television Festival, where she was discussing her illustrious career, Dame Maggie said she would like to see the Dowager Countess "croak it" in the opening scene of the film.
She said: "I was firmly convinced it would start with the funeral.
"I could croak it and it would just start with the body. But I don't know, they talk about there being a film but who knows? You might tell me if you do know."
Asked if she would agree to star in the movie if it was made, she replied: "I just think it's squeezing it dry, do you know what I mean?
"I don't know what it could possibly be ... anyway, that's not my problem."
During the discussion, the Harry Potter actress revealed she had never watched Downton Abbey as she found it "creepy" watching her performances back and called the attention she now received from the show's fans "ridiculous".
She said: "I haven't seen it (Downton Abbey), it got to a point when it was too late to catch up.
"I have seen some things a long time ago, and of course you're forced to watch it if you're at one of them premiere things. You always think 'why on Earth did I do it like that?'.
"It's always weird, of course it's weird. In the theatre at least you can say 'well, I'll have another go tomorrow night' but it's forever.
She added: "I led a perfectly normal life until Downton Abbey. I'm not kidding, I'd go to theatres, I'd go to galleries, things like that on my own and now I can't and that's awful.
"It's truly television, I've been working around for a very long time before Downton Abbey and life was fine.
"Nobody knew who the hell I was, it has changed."