“Oh congratulations!” declares Olivia Williams on seeing my immensely swollen pregnant belly, before pulling herself up, and lauching into full, self-effacing female Hugh Grant mode – “Oh please say congratulations are in order, because I really try to never congratulate anyone on being pregnant since I found myself cooing over this bump, only to discover it was just a big, fat woman with a bad back. You should have seen the look I got!”

From the outset, the 34-year old English actress is certainly not what one might expect from her screen roles. Despite having cornered the market in stiff upper lip types, in person she’s very much the gushing, jolly hockey sticks type. At any rate, she’s a far cry from her usual screen persona. From the distant object of Kevin Costner’s affections in mega-flop The Postman, to her widowed heartbreaker in Rushmore, to Bruce Willis’ aloof other half in The Sixth Sense, it’s fair to say that William’s frequently ends up playing ice-maiden types with considerable aplomb, and her latest role in Thaddeus O’Sullivan’s period drama is no different.

Playing the uptight society wife of Paul Bettany, who cheats on her with her own sister (played by Williams’ former real-life school chum Helena Bonham Carter) Olivia’s performance grants a warmth and complexity to a character that could have been decidedly two-dimensional, but that was precisely what brought her to the role, as she explained to me, during our recent meeting.

TB: In the next few months, we’ll see you in The Heart Of Me, Below and To Kill A King. Is your schedule always this gruelling?

OW: Oh no! I never work very hard. Never! It’s just the way things fall really. You finish filming, and then there’s this strange period, when you’re usually unemployed and then suddenly, all the productions you’ve worked on come out at once, and it looks like you’re a workaholic!

TB: Your character in The Heart Of Me is something of the classic ice-maiden. Are roles like that especially difficult, given that you’re very restricted in terms of emotional range?

OW: Well, I suppose I’ve ended up making a speciality of playing cold women, which seems odd to me and to people who know me well, because I’m not actually very repressed. If anything, I’m a bit too quick to confide, but there’s something about my face and physicality that makes people think otherwise, so I always get offered those kinds of roles. Strange, or at least it is to me!

TB: Your nationality must also be a big contributory factor to that kind of typecasting?

OW: That’s totally true. In particular the way I speak brings out so many preconceptions. At drama school for example, it was assumed that I simply must have been emotionally repressed as a child, because I’m English, and middle-class, and I speak as I do. Now my parents are extremely loving, warm people who walk around holding hands, or with their arms around me or each other, but no-one would believe that. I had one dreadful teacher who just couldn’t accept that I wasn’t in need of some kind of emotional beating, and that I actually had a touchy, feely upbringing.

TB: This is your third film with Paul Bettany. How come you keep getting thrown together?

OW: I know, I know! We have an interesting history. We first worked together on a film called Dead Babies – very good script and so on, but the title wasn’t terribly attractive, particularly in America, where abortion is one of the only political issues left. You’d try to explain that it’s only an expression like ‘Holy Smoke’ or whatever, but it was a bit of a problem really. But yes, I met Paul on that, and then I shot a scene for A Knight’s Tale with him, basically so I could hang out with him and his then girlfriend Laura, but it ended up on the cutting room floor, unfortunately.

TB: Only to resurface on the DVD...

OW: Oh wonderful! I’ve never seen it! When I read the script for Heart Of Me, someone else was attached to the male role, and I asked Paul to read it, because I wanted his opinion. He has a very, very good instinct about scripts. I knew I loved the writing, but I wondered how squiffy my judgement was, but he loved it. So when the other guy dropped out, I told Thaddeus that I had a friend who was about to be really big, but might easily be persuaded to work for tuppence, and dear Paul accepted, and has since gone on to better things in Hollywood.

TB: Like marriage to Jennifer Connelly?

OW: Exactly. Well, if ever there was a love-story, it’s them! They’re so in love. I’ve just seen them in New York, and of course, she’s expecting and it’s all so lovely. Happy, happy people! And he’s really about to master Hollywood as well.

TB: Which is in keeping with the usual order of things – Britain, then America – unlike your career, where you broke Hollywood first, and then started doing British films...

OW: I know, but of course what history doesn’t record is the seven long years spent in theatre! I tried to be in The Bill, like most other actors, but again, my education and the way I spoke went against me. They just didn’t have a lot of roles for middle-class, anally retentive women. They wanted convincing heroin addicts, so I never got my job in The Bill, and I really was struggling, and suddenly Kevin Costner rang me up for The Postman. The most unlikely thing of all time. It was great, but I should say at this point that I’m not so hypocritical to begrudge Hollywood actresses in London, given that I did it the other way around.

TB: I take it you’re referring to the recent Mail On Sunday article...

OW: Yes, and I keep getting asked about it by everyone. Basically, the article said that I hate it when American actresses come to London, and the Mail On Sunday had it written up as Olivia says – ‘Yanks Go Home’, and every syllable of it was untrue. Totally fabricated. Everything that was attributed to me, was made up by an extremely unpleasant journalist called Katy Nichol. I have to say that I have only ever been treated with respect and love when I ‘ve gone to America, and I just wouldn’t think that way, but it seems to be the one thing that everyone has read about me. If it wasn’t for America, I wouldn’t have a career, so saying something like that really would be biting the hand that feeds.

TB: OK, in the spirit of not biting the hand that feeds, perhaps I shouldn’t ask you what you think of your breakthrough film The Postman...

OW: Oh no, That’s quite alright. One of the advantages of The Postman coming quite late in life – well, in actress terms – because I was 29 by the time the film came out, was that I didn’t have any sparkling illusions about life, or about being a Hollywood movie star. I quite honestly only got into acting because I wanted to do Shakespeare at the Royal Shakespeare Company. I thought that the most I would ever do, in terms of being famous, would be to get a spot in the back row of a Merchant Ivory film. So just making that film was something I just enjoyed. I was upset for the people involved when it was panned. I thought people were vile about Kevin (Costner), and I thought a lot of great technical work went unnoticed, but no-one gets an Oscar for cinematography, if the rest of the movie has been panned, so a lot of beautiful work got shafted. So I was sad, but I wasn’t despairing or gutted.

TB: And of course, the fact that some of your films, like The Sixth Sense, were conversely successful beyond all expectations, must make up for The Postman as well...

OW: Well yes, it all balances out, doesn’t it? I was astonished how The Sixth Sense did in retrospect. It all bizarrely passed me by at the time. It’s only now I realise what great a triumph that was. I remember I was going out with a penniless Canadian writer at the time, and I was in his very dodgy apartment in this area of Vancouver called Cloverdale, which smells completely of cows, when my agent called up and said – ‘You have the number one movie in America’. I just got off the phone, and went back to listening to his James Taylor records. I really ought to have celebrated a bit more, don’t you think? And I really should have donned a spangly dress, or at least been having a manicure or something, but alas I was in cow country.

TB: Do you find that certain aspects of film-making differ wildly between America and Europe – size of trailer and so on?

OW: Well, trailers certainly are bigger over there. Obviously there are constants. Sound people spend a lot of time in corners with headphones and grips are grips wherever you go, but I have found that there is more pressure on you to look good in America. You keep hearing the opinions of producers – strange disembodied voices from on high who’ve decided that they don’t like the colour of your hair! In England if a producer said that, you’d just turn around and say – Well, I don’t like yours either!

TB: Actually, that was a major complaint from Helen Baxendale about working on Friends, which you joined her on for an episode...

OW: Well yes, and talk about voices on high! I found that really traumatic. The big problem with said voices is that weren’t high enough – they were right on set, commenting on every aspect of your appearance, and your performance – shrill voices going ‘You’re not funny! Shut up!’. It was tough. I have tremendous respect for the stars of that show, but I wouldn’t go through that again soon!