ABOVE: Sheridan on the red carpet

Despite the affection Dame Maggie and co. clearly hold for Smith, you get the feeling she still doesn't quite believe in herself.

"It’s nicer to just be real in yourself and I can’t do anything else, that’s why I act," she says at one point. "I don’t even know whether I’m that good at this but I’m doing what I love at least."

Such uncertainty is rare to come by in the self-promotional whirlwind that is showbiz but it's an approach that has seen Smith prized on Twitter, where she interacts with "a lot of young girls."

"I’m always really honest on there – at the end of the day, acting’s just a job and I’m still a girl with insecurities," she says. "So the girls are like, 'God, I can’t believe you feel like that too' because I think sometimes acting – I don’t know, you feel quite distant from people or people you see in magazines, you know, that type of thing.

"They give me advice, I help them out and it’s just like having a little cyber world of friends and family. I don’t know them all but it’s still nice, it’s kind of comforting. I live on my own with my dogs… tweeting!"

It's unlikely this way of life will change, even now Smith has Hoffman on speed-dial. When I suggest Hollywood is beckoning, she laughs it off and is quick to downplay her latest - and most prolific - foray into mainstream cinema.

"It’s been a one-off, it’s been a really special job," she says. "I don’t think I’ll get one like that again."

Watch this space, we say.

Quartet is in cinemas now

"I’m still a girl with insecurities"