The actress Geraldine James, 47, began her career with five years in repertory theatre and went on to take many leading roles in the West End, but she reached her biggest audiences on TV, in series such as 'Blott on the Landscape' and 'The Jewel in the Crown'. She is married to the actor Jo Blatchley, and lives in Sussex and London with their daughter. James has just finished working on a new TV drama, 'Seesaw', with David Suchet, 52. Suchet, an associate artist of the Royal Shakespeare Company, has made numerous stage, screen and TV appearances, but he is probably best known for his portrayal of Hercule Poirot. He and his wife Sheila Ferris live with their two children in north London

GERALDINE JAMES: The first time I set eyes on David was when I saw his photograph at the Gateway Theatre in Chester. When I left drama school I worked in children's theatre for six months, then went up to the Gateway to do my first ever rep job. David had just finished a season there, so there were photos of him all over the place in Waiting for Godot. He was Chester's star of the moment and the person we all struggled to match, because he had been hugely successful there and gone on to do other things. Everybody said he was incredible.

The first time I actually met him was about 15 years ago, when we worked together in Blott on the Landscape. It was when we were first shooting, and all I can remember is being totally embarrassed because I looked such a complete prat in that part. It was a lot to do with the make-up and clothes - I had a wig that took away half of my forehead, like a little bird's nest stuck on the front of my head.

The first job of an actress, for me, is creating relationships with other characters, and you have to achieve that almost instantly. My first day ever on film, I had to be in bed with Dennis Waterman in an episode of The Sweeney. They said "just hop into bed" and that was it, instant relationship - that's the nature of acting. Similarly, David and I had to create a relationship together, very quickly. Then something completely extraordinary happened, in that a relationship developed between the characters that was there in the book but actually was about the two people playing the characters. It is rare, and very precious, when that happens.

Blott was a fantastic job, because it was a six-parter, and in those days we had about six months to shoot it in. So you had plenty of time, and we were in this beautiful countryside in Powys - I remember driving to work in summer and just thinking: "I can't believe I'm driving to work." I look back on those days a lot - I've still got a photograph of the two of us sitting in a hammock in the grounds of this immense mansion where we were filming. It was a wonderful release for both of us to play those nutty characters, characters that weren't great romantic leads, where nobody was leaning on us.

I think the reason we work so well together is that we work in the same way. There's a sort of truthfulness that's all about the character which is common to both of us. We have had similar experiences as actors, starting in theatre, moving to television. But it's actually more about responding just as a person - you know, when you meet somebody you have something in common with. It's not particularly to do with respect or admiration, it's to do with liking, and then if you like somebody you ask them questions and you find their answer goes along with what you think too. We like the same actors, for instance; and chances are we would like and dislike the same things in the theatre or film.

It's very comfortable to work with somebody that you know well. I was sent Seesaw and I read it, and they asked me if I wanted do it, and I said: "Only if David Suchet plays the husband." They went: "Guess what, that's exactly who's doing it." Which was great. In Seesaw, we played a couple that had been married for years. That's a long time, but we could slip into it very easily.

David and I worked together very intimately on Seesaw for six weeks; then, because he finished filming before me, he was gone, and I felt quite bereft. He went straight off to America to make a film. When he got back he phoned me and we went to the theatre together.

Fortunately, because they have worked together (in that Chester production of Waiting for Godot, strangely enough), David knows Jo as Jo, not as my husband. I know Sheila as David's wife but I've known her for long enough - we were virtual nobodies when we did Blott. And so we are all like mates.

I like good actors, I love seeing good acting, and the other thing I like doing is laughing, and that is easy with David as well, we have a very good time. I like his humour and his integrity. He likes people, he's very interested in people, he's very warm, he's a nice guy. Our main difference is that I'm a very untidy, scatty person, and he's fastidious and neat. We couldn't live together, I think we'd drive one another barmy in a minute.

We will certainly stay friends. If not, something will have happened that will have made me extremely sad because it means something has come up and rent us asunder. I hope that doesn't happen. Friends become more important as you get older and give you a sense of where you are. They are like the guy-ropes that hold your tent in place.

DAVID SUCHET: The very first time I really met Geraldine was in the make-up room when we were in Ludlow for Blott on the Landscape. Her back was towards me and she was facing the make-up mirror. I'd seen her before then of course, but this was the first time we spoke. My first impressions are still very clearly in my mind: they were of someone with enormous warmth. I can't remember what we talked about, but usually when actors get together at the beginning of a programme they talk about the show.

I don't think I immediately thought we'd be friends on a personal level, but there didn't seem to be any of the barriers that can be put up between actors when they first meet: sometimes there's a feeling of slight abrasiveness before you get to know one another. I think my first feeling was more one of relief, because we had to go through the whole six episodes together and I thought immediately that we would get on as professional colleagues and that was the most important thing of all.

Acting is such a strange business, you're thrown together so quickly and you're expected to work together with an intimate knowledge of each other within a few hours of saying hello. Sometimes it can be very difficult. I think it boils down to fear, because one's always frightened approaching a new project, as anyone is who's facing an important piece of work. So to start a whole new job is a very nerve-racking experience, and I think that's what makes a lot of actors work hard at breaking barriers and getting on with each other very quickly.

It is a terrific bonus if that bonding happens quite naturally, and that's where Geraldine and I were very fortunate. I think out of so many people I've worked with in nearly 30 years, Geraldine would be right at the top of the list. She's very generous, she's not competitive, she's very honest in her portrayals, very concerned to get the moment and the character and the relationships right; she will fight for what she believes is right. In fact, I would say that she's one of the very best actresses we have. We work in a very similar way. We care about the same sort of details. We care about being precise, we care about getting it right. So in a sense when we've worked together, I felt a great strength in doing the right thing at the right time in terms of the characters.

I've always been a great fan of Geraldine's: I'll go and see her work and I'll always slip backstage and say hello if I can. She is such a terrific actress that I'll always go and see her, in the theatre especially. One of her most memorable performances for me was in the Merchant of Venice. It was starring Dustin Hoffman, but for me it was starring Geraldine James - she was the best Portia I've ever seen, ever. She was wonderful in the National's Cymbeline, too. We come from very similar stables - we are both theatre-based, both of us then moved into TV, both of us had our big hit series - hers was The Jewel in the Crown, mine came slightly later with Poirot. So we have a similar background and that's a great bond.

It was terrific coming back together in Seesaw. I was offered the role a long time ago, when I was doing Who's Afraid of Virginia Woolf in London last year. I heard that when she was offered the role she said she'd only do it if I did it, and ironically I was already on board. She saw the role was dead right for me and it was absolutely gorgeous to work together again. We slotted right back into a good, easy, giving, generous professional working relationship. I was very sorry when the job came to an end and I'm longing to work with her again. The first series that we appeared in, Blott on the Landscape, I was her cook, chauffeur, handyman, whatever, and in the end, they get married. In Seesaw, we start married as husband and wife. I think we make a very good couple, I really do! I think we work together very well as husband and wife. It doesn't feel funny, it feels like a blessed relief - if you're playing at husband and wife you don't have to work at it when you already have an easy relationship between you.

Geraldine has a great sense of humour, a great capacity for laughter, a positive attitude, and generosity. Geraldine and Jo, and Sheila, my wife, and myself - we all get on very well and we all go to the theatre together. I think what's nice about it is that we're not theatrical - neither of us is theatrical. I'm not at ease with theatricality and I don't believe Geraldine is either.

I hope we'll know each other until we stop acting and after. I'm very fond of her indeed and very fond of Jo, too. I'm ever the optimist and I'm convinced that if nothing untoward happens we will know each other for always.

'Seesaw' starts 12 March, 9pm on ITV.