Brenda Blethyn was already an established theatre actor when she moved onto TV screens in the early 1980s. Programmes she's appeared in include Yes Minister, the sitcom Chance In A Million, in which she starred opposite Simon Callow, and BBC Shakespeare adaptations. On the big screen, her portrayal of brassy, factory-working mum Cynthia in Mike Leigh's Secrets And Lies won her an Oscar nomination. Other roles have included Ida Stubbs in Little Voice, Mrs Bennett in Pride & Prejudice, and now comeback comedienne Jeanie Dwight in Clubland.

What attracted you to this film?

I think it's beautifully written, the journey of the boy finding that love and sex and romance for the first time. You don't often see it as pure and as innocent, and I think as real as that on screen. It's honestly done, [showing the]z` embarrassment as well.

I'm fascinated by embarrassment and this character, Jeanie Dwight, is embarrassing. I loved the opportunity to do that. She's not particularly sympathetic and it's because she's a strong-willed person. We tend to not feel any kind of sympathy for someone who's as strident as she is, particularly if at the same time you can see the other side of the coin. I knew that the audience was going to be judgemental, but I thought, that's not going to frighten me off doing it, because I think it will resonate with a lot of people.

How did you manage to make someone who's acting like such a cow so likeable?

I think if you'd met [Jeanie's] family a week earlier, without the complication of her getting her back up over [her son's new girlfriend] Jill, you'd have seen a different set up and you wouldn't have seen a cow. But now she is behaving like a cow. There's no two ways about it.

But it's just that her son is behaving uncharacteristically, coming home late, wanting to stay out all night, and she doesn't know why. She wants the best for her boys - he's just starting up this removals business, and he doesn't want him to go and upset it all on the first encounter he has with a girl. She also knows how shy he is, so she knows that it'll be the girl doing the running, and that what gets her back up.

Ordinarily her sons quite enjoy the raunchiness of Jeanie. Their mates would say, "Oh your mum's a laugh. I wish my mum was like your mum." But now she knows she's behaving badly. We all do it, we've all said things we shouldn't have, and once you're on that rollercoaster it's difficult to get off.

What was it like filming the scenes where Jeanie puts on her act in the clubs? Had you done any stand-up before?

No, no I hadn't. We did quite a bit of research, and it was well written, and we had help from a wonderful stand-up, Jo Brand. I tried to get in the mindset of a standup. I'd go home and imagine I was really going to have to go on somewhere, and work out a routine. I came out with some quite good jokes, actually, but we couldn't use them because Jeanie's not very good. Her jokes have got to be borderline embarrassing.

There was one club we went to, there was a bloke who did not get one single laugh the whole evening. Jeanie Dwight would have done better. But he didn't look at all deterred. He'd have come off there, be handed his pay, and go on the next day and have another go. Not one single laugh.

Jeanie's act is very much the sort of variety act that went out with the 70s, isn't it?

The audiences I was playing to out there were of that generation, and they kind of liked it. They were pensioners, and liked the double entendre and those naughty jokes about sex, because that's the only sex they see in their lives, probably. It's kind of innocent, although it's a bit on the raunchy side. It's old hat. So that went down quite well actually, at the clubs I played at.

One woman said to me after, "I loved your act Brenda. I think I might have seen you in a club in Melbourne." "Oh no," I said, "thank you for your nice comments, but I'm just a humble actor." She says, "Now, don't put yourself down." Sweet.

One of the most painful scenes in the film is when Jeanie goes to a completely disastrous audition...

That's my favourite scene. It's so embarrassing, it's painful. Somebody in America said, "Couldn't you have got a little help with that scene, honey?" I said, "What do you mean?" She said, "Surely you could have got some help, it was painful to watch." I said, "It was meant to be! I did it well then!" She totally missed the point. It expressed all that humiliation, that gut-wrenching feeling that you're not wanted. My heart went out to Jeanie [in that scene].

You're quite well known for this sort of realistic, closely-observed role. What's the appeal?

For me, it's about finding the truth of it. One person there might find it funny, that person might find it tragic. It's not for me to decide for them. It's just finding the truth of it, and I think perhaps we did that. I do particularly like finding the place where you don't know whether to laugh or cry. Some people might say, "Oh, isn't she horrible," and I say, "Yeah, she is, today, she might not have been last week. Don't think that's how she is always, that's how she is today." And if it makes people think, and change their minds about decisions they make about people, that someone you might meet on the bus or on the street who's a horrible person, well, they're not like that all the time, it's a good thing.

Why should people go and see Clubland?

Clubland I think is very uplifting, it'll make us feel OK about our own little idosyncracies and the little tantrums that we might have, and we all have them. Sometimes we all behave badly, every single one of us. All is not lost - you can redeem yourself.

Clubland opens in UK cinemas on Friday 21st September 2007.