Alison Steadman, 50, was born in Liverpool. She separated from her husband of 23 years, the director Mike Leigh, last year; they have two sons. She lives in London. Janine Duvitski, 44, was born in Morecambe. Her partner is the actor Paul Bentall; they have four children and live in Richmond, Surrey. Both actresses have made numerous cinema, theatre and television appearances, and are particularly well-known for creating the roles of Beverly and Ange in Mike Leigh's classic comedy `Abigail's Party', first televised in 1977. Alison and Janine are currently working together on a production of Sir John Vanbrugh's Restoration comedy, `The Provok'd Wife', at London's Old Vic theatre

ALISON STEADMAN: My first real impression of Janine was her flying into the rehearsal room, the very first day of Abigail's Party. Nobody knew what it was going to be or what we were going to do, we were just five actors and a director getting together in this church hall in Regent's Park. Janine was very, very late, and she was in a terrible state, something had happened with buses or something. Being late on your first day is terrible and I can remember Mike [Leigh] calming her down, reassuring her that it wasn't the end of the world. She says she was two hours late, but I can't believe it was two hours really. After that, she was never late again.

Working the way Mike works, it's not like ordinary plays - he works individually with each actor to begin with, so we didn't get to know each other straightaway - maybe we'd meet up for a quick coffee. It wasn't until we started doing improvisations and then putting the play together, that we really saw each other. We soon established that we both had a pretty good sense of humour, and we were very dangerous company as far as corpsing on stage was concerned. Nothing's changed; we were running through some lines for the play we're doing now, and there was one line that made me corpse, and she corpsed, and she said: "Oh my God, that's going to be a dodgy line. It's going to be like the leather-look line in Abigail's Party." My character Beverly during the play was going on about her beautiful couch and how it had cost a fortune, and Ange, Janine's character, assumed it wasn't real leather, but "leather look". I used to dread this line, I'd be taking deep breaths and looking away - it used to crease me up. We're not similar in character, but we have the same basic understanding of the fun of acting, having a good time, having a laugh and a joke, but at the same time taking it deadly seriously. So we were very much in harmony, working that way.

Abigail's Party was so special, I don't think those sort of things come round twice really. We've been friends since then, but you can be friends with someone without living in each other's pockets. After Abigail's Party we'd go and see each other's plays - she comes and sees stuff I'm in, I go and see stuff she's in. She's funny in everything she does. Most recently I enjoyed Cloud Nine, because in it she played a little boy, then, in the next half, an elderly woman and she does both so superbly. We mainly kept in touch via other people - sending messages back and forth, "Janine sends her love" and stuff like that. I had a baby four months after we did Abigail's Party on television, and I got very involved in being a mum; Janine's a few years younger than me, that happened to her later on, so we were on different paths for a bit.

It's great to be working together again. She's playing a French maid, and as soon as she starts this accent I have to steel myself in fear of creasing up. It's a very wordy comedy, and the stuff that me and Janine have to do should be funny, if we can make it work. I'm playing Lady Fancyfull, this terrible, vain, upper-class, rich, pampered, self-indulgent woman who thinks the whole world is madly in love with her, which isn't true. Janine is this very sparky French maid who brings a sense of naughtiness into Lady Fancyfull's life and tempts her into bad ways. We've got a lot of running around in disguise and hiding in arbours to do.

The main thing about Janine is that she's got a terrific sense of humour, we laugh a lot, and she's a very, very talented actress - but she's not precious about it, it's just something she can do rather than something she makes a huge holy thing of. She's just a natural, really, an instinctive actress and she's not at all pretentious, she's a very funny, relaxed kind of person. You're always encouraged by working with people like that - someone you know you can trust on stage. With some people you do think, "God, it's so-and-so, they'll be a bit this or that", but with Janine you don't at all. We can go off and have a drink together and a good laugh. The other day, we were crying-laughing, on the couch with our heads buried in the cushions, goodness knows what we were talking about but it just tickled both of us. Janine is a very open kind of person, she's not somebody who you get to know as you peel off layers and layers and layers. What you see is what you get. She's completely scatty, in the loveliest way. She's a very emotional, feely kind of person, but she's also got another side to her which is completely chaotic and mad, quite loopy and anarchic - it's a very endearing combination.

JANINE DUVITSKI: I met Alison on the first day of rehearsals for Abigail's Party. We had three or four weeks where we all worked individually with Mike on our characters, so I would just see Alison in passing while I was working on Ange. She's very natural and unpretentious - I won't say ordinary, it sounds a bit rude, but friendly and warm. After about four weeks of just nodding at each other, Mike said to me: "Right, your character's going to meet somebody, and the important thing is to stay in character and go with whatever happens." And I remember so clearly her knocking on this door, and coming in, in character as Beverly. I was just astounded at the difference in her, really. I'd never done Mike's work before, so I didn't know that much about it, and here was this person who had become so different and so clear in character. So instead of doing my character meeting her character, Ange meeting Bev, I just dropped my character in shock, I was so impressed - instead of it being an impro, it was Beverly meeting Janine. At the end of it Mike went off to speak to her on her own and came back in to speak to me and said: "What happened?" I thought, "Oh no, I'm hopeless at this", because she was so fantastic. Then a couple of days later on the television was a repeat of Nuts in May, and there she was, completely different again!

Anyway, we got it together, Mike kept working with me, and we eventually started working on the actual party in detail. And she just made me laugh so much. I think people think that in Mike's things it's all very serious all the time, and sometimes it is. But at the same time you're hearing all these made-up lines for the first time and Alison and I had a particular problem; Bev was telling me all about her leather sofa and I said, "Oh, we've got one like this", and she said, "Leather?" and I said, "No, leather-look." Every time we got to that bit we laughed. And we've laughed a lot ever since, really.

The biggest bond between us is humour. She just makes me laugh. She's also a very genuine person. Over the years, because we've been busy and had lots of kids and all that, we've been to see each other in plays, and when we do meet up we catch up really fast. I remember going to see Naked, Mike's film, and we were chatting afterwards, and he came up and said: "You're meant to be discussing the film, not children!" I live in Richmond now, which is right the other side of London, and you often don't get to see the people you want to see, so it's good to know that working together again we'll see a lot of each other. We'll have a lot of laughs and a few drinks - I remember in Abigail's Party we both used to have a bottle of Pils in the interval to get us going for the drunken second half, without us being too drunk.

Another thing that's good about Alison is if anything goes wrong. I remember in Abigail's Party a peanut got stuck in my throat. I had to eat a lot of things, cheese and pineapple and all the rest of it rather quickly, and I got this peanut really wedged and I was croaking on with the next line, and Alison said "All right Ange? Got a little peanut stuck in your throat?" That's one of the good things about improvisation; normally with a play you're frightened of going away from the lines, but that time we went on for another 15 minutes. In The Provok'd Wife I play a French maid so if my French goes wrong Alison will be able to help me out. The play is difficult, because it's all full of topical jokes and comedy of the manners of the time, in the same way that Abigail's Party was of the Seventies, but whereas that was instantly recognisable, this one is very hard to reach an audience today.

We come from the same sort of background of work. We both went to the same drama school, East 15, and we've both worked with Mike. She's like me in that she didn't go to university. We're not particularly intellectual, we just approach it by instinct. She left me a note when she'd been offered the job, saying she found the thought of the job really frightening, which I always do - that feeling of: "Oh God, I'll never be able to get away with it this time." But you think: "God, all those things she's done and she still feels the same way ... " She's the unstarriest person you could get.

! `The Provok'd Wife': Old Vic, SE1 (0171 928 7616); now previewing, opens Fri.