Martin Freeman shot to fame back in 2001, when he starred as the love-struck nice guy, Tim Canterbury, in Ricky Gervais' spoof documentary series 'The Office'. His new film, 'Confetti', is another documentary-style comedy about three couples who enter a competition to create the most original themed wedding. Martin plays one half of a couple who decide to make their wedding into a musical extravaganza.

There was no script on 'Confetti', all the actors improvised their lines, and they were instructed to stay in character whenever they were on set. The result is a very funny and touching film about the trials and tribulations of getting married, that will ring true for many couples.

There's a really big difference between your last film 'Hitchhikers Guide to the Galaxy' and 'Confetti'.
Yeah, absolutely. We started filming this about a month after we'd finished doing Hitchhikers. They are completely different in terms of size and budget and subject matter, and there was the process of going from something where there'd been not only a script, but a story that for 25 years some people had almost lived by as a religion, to something that was completely untried and untested and improvised. So it was a very, very big switch, but a very exhilarating one.

What made you want to take the part in 'Confetti'?
Debbie Isitt [the film's director] contacted me ages ago, probably early 2003, saying she had an idea about an improvised film about three couples getting married. The only thing she had to put to me was that the person she wanted me to marry was Jessica Stevenson. I'd never worked with Jessica, and always liked her, I think she's a very good actor, so that was the attraction. I thought Debbie was really nice, in a barking way!

What was it like working without a script and having to improvise everything?
Quite frightening really! It was a shock to me, I thought I'd be quite good at it because I'd done bits of improvising and bits of what I call 'loose' stuff when you've got a script and your remit is to kind of play around with what's already there. There's such a huge difference from that when there is nothing - it's a huge difference because you've got nothing to refer back to, you've got no source material to say 'yeah, but in the script it says this'. So there is nothing to go back to, other than a sort of overview of a story that we all had in our minds.

So it was scary, I found it at times very hard, and at times I wasn't very good at it, and I just had to sort of get better at it as the filming process went on. And Debbie was very clear about what she didn't like, which was most things I did! She was very clear about when something wasn't working – you know very often when something's not working, but she was very good at pinpointing why it's not working, and it's usually very simple page one things like, 'you're not listening to each other'. We might all start speaking at the same time, and obviously that's no good for either an audience or an editor. So it was like going back to school in that sense, it's the real thing of honing in your listening and knowing when it's your turn to speak.

Did you ever just totally dry up?
No, to be honest. But that's not to say that I was always brilliant! I have a similar sort of problem, but manisfested in another way. When someone throws you something in an improvisation, I've never found that I dried up, but you can find that you start speiling – so that would be my problem, as a pose to just drying up. I had verbal diarrea and that's something that isn't helpful to the plot or isn't helpful to the scene, or isn't funny.

You've got to keep a lot of balls in the air, you've got to be funny, you've got to keep germaine to the story, you've got to be naturalistic, it's got to be real, you've got to stay in character, and be funny and improvise and listen and not speak over people - it's quite a daunting task!

Did you ever kick yourself at the end of the day because you wished you'd said something different in a scene?
Honestly, no. And again that's not because I had all the good lines, it's because I'm quite lazy and once I've gone home I'm just thinking about egg and chips. If I was a slightly more diligent person I probably would be thinking about it. Once I went home, I went home. Normally, you'd be going home and studying the script. There's no script to study, so there's more time to think about egg and chips.

The film's made in a documentary style – do you think that made improvising easier?
Maybe, because in a documentary it doesn't matter if you stumble over words because in real life people make mistakes and people do talk over each other or whatever. So in that sense you probably can literally 'get away with' more and it's easier to look natural in that circumstance.

The way the film was made means that everyone had a part in deciding how the story would turn out. Was that a daunting prospect?
It is. Do you know what, I probably didn't see it like that at the time but I guess that in retrospect it is. I think if I'd seen it like that I would have thought it was too much responsibility and run off crying! But, yeah, I guess collectively we all did have the responsibility, but with the knowledge that ultimately Debbie was the director and she was going to be the one who said what's in the film. She did a very good job of assembling people who can take the ball and run with it – even though I did find it scary sometimes.

I think everybody probably went through moments of thinking 'Christ, what have we got ourselves into?' It is a very good cast, and it's a cast of people who are more than just people who can say scripted lines – it's all people who can bring something to it, and they all came aboard for the same reason I did, to take the risk on something they saw had heart.

You had to sing and dance for your wedding scene – how was that for you? Have you done musicals before?
Some steps I didn't find easy to pick up, to be honest, but I loved doing it, I really enjoyed doing it. You know I think most actors are show-offs and I think most actors at some point, whether they deny it or not, have spent afternoons in front of West Side Story – me in particular! I'm a big fan of musicals. I haven't been in any professionally – in drama school, youth theatre, and I always really enjoyed it. And, you know, I wouldn't be brilliant at it but I wouldn't be awful at it - I was ok, I could carry a tune, I could move, but it was really good fun.

We couldn't improvise that on the day, so we would rehearse and rehearse, but still keeping in character. So I really liked it, I did find some of the steps a bit intricate, because I've not done anything like that for 10 years, since I was at drama school, so I was a bit rusty. But it was fun – at least I knew what my lines were, I knew what my steps were and that was quite a nice little oasis of calm in a maelstrom of thinking, 'what am I saying?', 'I was awful!' or 'that was terrible!'

At one point in the film you get angry with your mother-in-law, who's played by Alison Steadman. It looked very real!
I hated Alison! No, of course I didn't. No, I think that's where the improvised bit of it helps because, take that case in point, all we knew was that the wedding planners were going to come round with a suggestion for where they've got to with their development of the wedding style, and all we know is that we going to have a look at it. I don't know that someone's going to be as negative as they're being, I don't know that Sarah, Jess's sister is going to start flicking things around.

My experience of that scene was just to let it get on top of me, I didn't know that I was going to explode, we did not know how that scene was going to end. It has it's own shape, it's own life and it ended that way because that's the way it went in that take. Which is really, really exciting and genuinely part of the reason you want to be an actor because you don't quite know what's coming next and you like the uncertainty of the life – you don't know whether you're going to be employed or unemployed - and actually to have that within a scene, you don't know who's going to speak next, if someone's going to leave, you don't know if someone else is going to come into the room without you knowing it. It's really, really exciting, but as I said before, frightening.

What would you think if your girlfriend suggested a 'themed wedding'?
That she had lost her natural mind! It's not my cup of tea in real life, the themed thing. It doesn't work for me, but maybe that's because I'm an actor and my whole job is spent in the spotlight, with people either hating you or adulation, you're the focus of attention. Maybe if you're in accounts all your life, and you never have your day in the sun or you never have your moment in the spotlight, then maybe you do want to come in on a bungee-jumping thing. But for me it would just slightly detract from the fact that I just wanted to tell someone I loved them.

Which was your favourite wedding in the film?
Our one! Probably everyone would say the same thing, their own one. I felt quite attached to it and it was quite an emotional attachment because of how much work we put into it. Until I watched the screening I didn't know how it would turn out, because we filmed three different endings with each one winning.

What was your inspiration for your character?
I wasn't doing massive workshops on perfecting the walk. I think sometimes imagination is an often overlooked thing in research and preparation. All we're doing is telling stories. When you're telling a story to your baby, you're not thinking, 'I'm telling her Red Riding Hood, I'm going to have to go and get devoured by a wolf!' Imagination, I think, is what we overlook and it's not like I had to imagine myself fighting dragons, it was a bloke from the South of England who's about to get married and my brief was not to go that far away from myself. The reason I was employed by Debbie in this particular job is that she just wanted me to be sort of like me. So there was no massive research or anything.

You're always playing the nice guy – are you looking for the chance to play a different type of character?
Yeah, I wouldn't mind. That wouldn't be the first consideration over and above the story or script. I'm asked this a lot, why do I always play the nice guy? Playing something like a rapist is all very well, but it has to be right as well, it has to be a good piece of work. I wouldn't want to just do it for the sake of inflicting that on the public. I'm not really that bothered, I just want to be part of the telling of stories. And I see why people ask me to do things that are a bit like me; because no-one could do me as well as I do!

Confetti's a very British film, is that why you chose it?
I love everything about Britain. I love living here, I've got no intention of moving away. I've got family here and it's everything that's made me. But it's not particularly because it's a British film, you know, I've done American films in the last year, and really enjoyed it. It's just for me about whoever approaches me with a good story to tell. And something that I feel I can be proud to have been in. That's mainly what drives me, more than if I'm being perceived as being too nice, or I'm not playing enough killers, or whatever. At least I know why I'm doing them, even if people don't agree. 'Confetti' certainly is the film that I thought we were making, so that was good enough for me, when I saw it I thought, 'it's funny and it's moving - that'll do for me.'