Michelle Williams on Blue Valentine

When it comes to Oscars, the Best Actress category usually reflects the downside of modern Hollywood. While everyone gets excited about the Best Picture shortlist – so much so that it had to be extended to ten – and coos over Best Actor, the Best Actress category sometimes struggles to be filled with five feature-length Oscar-worthy performances. This is no criticism of the talent that's out there, just a sad reflection of the way things have been lately: up to now, Hollywood simply hasn't been investing in leading roles for women that are rich as the roles available to men. Where were the female equivalents of Up In The Air? A Single Man? The Wrestler? There Will Be Blood?

This year, though, something has definitely changed. A glance at The Bafta longlist suggests the selection process this year will be brutal. The one to beat is Annette Bening as a lesbian mother in The Kids Are All Right. The young pretender is Jennifer Lawrence, playing a white-trash avenger in Winter's Bone. The dark horse, appropriately enough, is Black Swan's Natalie Portman, as a disturbed ballerina. And this is before we've got to Nicole Kidman's wonderful performance as a grieving mother in the achingly poignant Rabbit Hole, Hailee Steinfeld's breakout appearance in the Coens' honest-to-goodness western True Grit (mystifyingly treated as a Supporting role at awards so far), Noomi Rapace as the brittle, steely-eyed Girl With The Dragon Tattoo or even Bening's co-star Julianne Moore, who plays her ditsy lover.

But for my money, one of the standout performances comes from Michelle Williams, who in Derek Cianfrance's Blue Valentine delivers an exquisite performance that cements her status as one of the most interesting actresses working in the US today. Her CV says a lot about her; the most commercial move she's ever made has been Martin Scorsese's Shutter Island. There are no studio romcoms there, no comic-book franchises (Halloween: H20 is the furthest she's been down that road), and the directors she's worked with – Ang Lee, Todd Haynes, Charlie Kaufman, Kelly Reichardt, Sarah Polley – are some of the best on the fringes of mainstream cinema.

Blue Valentine, in which she co-stars with the equally excellent Ryan Gosling, is another hit to add to that list; soulful and moving, it works because it's so human. I remember seeing it at Sundance last year, and what proved to me that the film had legs was the way it was discussed for days after the screening. As the film completed its run at the festival, conversations could be heard in every wait line, in every bar and on every bus. Because, in some ways, Blue Valentine is a whodunnit. It's the agonising story of how two young people fall in and out of love: Dean's a removals guy, Cindy's a nurse, they meet in Brooklyn, move to Pennsylvania, have a kid, and nothing else really happens except two extraordinary performances that intertwine and break apart across a fractured timeline. Does Cindy push Dean away? Is Dean really so bad? Is Cindy lashing out? Does Dean deserve it? The film leaves all that to you.

Speaking to Michelle this week, I was not surprised to find that this was not just another role for the 30-year-old but a rather remarkable labour of love...

When did you first become involved in Blue Valentine?
I think it was the summer that I was 21, maybe 22, and I met Derek in Lower Manhattan. I met him for lunch, and that turned into dinner, and that turned into a long walk, and that turned into night falling. And I've been wanting to make this movie ever since then.

Was Ryan always going to be Dean?
As far as I had ever known. I had never heard Derek mention anybody but Ryan, and he came on board shortly after I did.

What attracted you? Was it Derek's passion, or the character, or the story?
It was a combination of all those things. They were all working simultaneously to put me on the hook, really, and what I loved about it changed. Because at many points over the last eight years we've been about to make this movie, and so every time we were about to make it I would go and re-read the script. And I found that it's hard to trust your taste when you're 21 or 22! (Laughs) Which I also think the movie itself is about: how do you stand by a decision that you make when you're very, very young – possibly even a shadow of the person you're gong to be? So every time I revisited the script I found something else that engaged me.

Given this long gestation period, did the script evolve much over the years?
The bones were always there, I'd say, but things kept changing, slightly. I believe that Derek wrote something like 66 drafts of it! So it was in flux.

All the reviews of the film have focused on the performances. How do you gear up to do that kind of work? Does it require a lot of preparation? Or is it something that an experienced actor should be able to do from a standing start?
(Pause) I've never had a working relationship like this on screen before. I've never spent so much time with another actor, I've never had this kind of trust with somebody before, because of the way Derek allowed us – and encouraged us – to work. For the first part of the film, when Cindy and Dean are falling in love, Ryan and I had very little experience of working with each other, and Derek wanted it exactly that way, so that we were really getting to know each other instead of just 'acting' getting to know each other. And so there was no rehearsal, no prep time, that we spent together – we were in our separate corners.

But how did you prepare for the heartbreaking second half of the movie?
Well, then we took a month to learn how to unravel this friendship, this affection, this love that we'd built. We took a month to learn how to unravel that – how to set it on fire. How to fight. How to hate. How to be annoyed. How to have the hairs on the back on you neck stand up when the other person enters the room. That was pure Derek – he made the space for that to happen. Because time is money, and time is what you don't have in film, especially independent film. So for us to have that separation time... (Sighs) I don't know what we would have done without it. It was supposed to just be a week or something – eight days, or ten days, And it was Derek who realised we weren't ready, so he fought to extend it.

How did you work on a character like Cindy? Do you like to work on it yourself, or do you like it to be clear in the script? (Tentatively) I suppose I like both. (Decisively) Yes, I like both. I like to do my own little bitty whatever-they-are add-ons, and have ideas about things. Come with an open mind. Which can be harder and harder to do when you've worked for a very long time. It's hard to keep giving your trust very freely, I find. But you never know when you're going to run into a director that's going to change you and excite you, the way Derek did.

Do you like to people-watch? As you become more well-known, does that get harder for you to do?
Well, a lot of Cindy was born in that month off, because I was spending time in the area that we were shooting in. I was going to the mall, going grocery shopping, doing these things as character-building exercises. I went to go visit the local nurses. And I would see these women who live in this area. Slowly, shades of Cindy would emerge – like this kind of worn-outness, which is very not New York City. In New York City, women have an ability, even after having had kids, to stay on top of their looks, to stay on top of the way they dress, stay on top of their energy levels, stay on top of their health. And that, I found, didn't exist in this area. I suppose maybe because a lot more importance is put on that in the city, or maybe there's more money in the city, where people can afford things like child care and facials. But that's not what I was observing in the community in the area around me, so that was something that I incorporated into the character.

Because the film was in pre-production for so long, have Cindy and Dean stayed with you perhaps more than most of the characters in other films you've made?
Oh yes, definitely. Sometimes I think of them as old friends now. Like I think to myself, 'I wonder what happened to Cindy and Dean. Do you think they made it? I wonder if they're doing OK…' Because they were both such a part of me – and of us – for such a long time. It wasn't a fun place to live in, towards the end, so I don't altogether miss them, because it was so toxic at the end. (Laughs) I don't miss that part!