Halle Berry has had something of a rollercoaster career. For every high such as Spike Lee's Jungle Fever or her Oscar win for Monster's Ball there have also been lows such as Gothika and Catwoman. She's also played super-heroine Storm in the X-Men movies and made 007 go weak at the knees in Die Another Day. She's back on serious form for her latest, Things We Lost In The Fire, which finds her as a mother attempting to cope with the sudden death of her husband. Here, she tells BBC Movies why she fought so hard for the role and discusses her own impending motherhood...

First of all, congratulations on your impending motherhood. You must be very happy?

Yes, it's a very miraculous time of life.

Things We Lost In The Fire is a really emotionally involving film. But I understand you had to fight hard to get the role?

Well, I had to throw my hat in the ring. Many actresses wanted this part, and rightfully so, but I was one of the people to do so. There are so few good roles written for women each year and when one is written like this, every actress in town covets the role.

What appealed to you most about the role?

The subject of what Audrey was dealing with - loss. It scares me to death and so therefore like a moth to a flame I felt like I needed to learn about this and discover about this part of life. I loved all the characters. I felt they were really interesting and complicated and very life-like.

Did you do any research into grief?

I did because I haven't lost anybody in my life. I read a book by Joan Didion called The Year of Magical Thinking. She'd lost her husband and that was really informative. It laid the landscape for what grief was. I also talked to grief counsellors and to people who had actually lost people. I then realised that I had people all around me who had lost people, but I had just never taken the approach of picking their brains about it. I was only the support person in their life when it happened and now I was more of an investigative reporter asking them all the intricacies of what they emotionally felt.

Was it a draining role to play given the nature of the emotion you were asked to portray?

It really wasn't. People often think that but sometimes it's more draining to play a role like Storm in X-Men, when there's not a lot of acting going on and you're working against a green screen. It can sometimes be very boring work at times by the nature of what that process is. But this, every day was dealing with people, it was acting, it was a slice of life, it was communicating with one another all day long. It was food for the soul. So, it wasn't as draining as one might think. Rather, it was actually inspiring to work that way.

One of the most inspiring lines to emerge from the film is to "accept the good". Is that something you've always tried to adopt in life?

I think it's a great message and we should remind ourselves of ways to accept the good because I think in our nature we're negative people. Somebody can say 10 wonderful things and then one bad thing and I'll be damned if we don't highlight the negativity. I think it's in our nature and it's kind of sad really but it's a good reminder that we should really try and focus more on the good. There is a lot of good out there.

I imagine the casting of your children was very important but they project an authentic innocence, don't they?

Well, it's credit to Allan Loeb, the writer. He wrote them as innocent children. Sometimes in the movies you see kids that speak like a 30-year-old and are so precocious that it's hard to believe that they're little children. But Allan wrote them as kids. They do, say, act and behave as children their age do.

What was it like working with them? Was it difficult at times? Or did you develop the maternal instinct very quickly?

Luckily for me I had that instantly. I realised that I had a really solid maternal instinct. When I got them it wasn't long before I felt we had a connection that felt real and authentic. So being with them was really one of the highlights of my days. I would love it when I saw Alexis [Llewellyn] in the morning and she'd run up and give me a hug. The other beauty is that Susanne [Bier, director] picked kids that didn't want to work 12-hour days; so they got tired, they got cranky, they didn't want to work.

There was one scene where we're all sitting around the table and Audrey is deep in her grieving and just wants a little peace and quiet. She just wants them to eat some food and to sit there and be still. But Micah [Berry], the little boy, kept laughing in the take and I, Halle, was getting frustrated because Audrey, my character, was trying to do this thing. All I could feel to do at that moment - because I was feeling very motherly towards them - was grab his face because I got fed up. That wasn't scripted, that was just there in the moment because he wouldn't stop messing up the scene [laughs]. It was moments like that that made me feel very much like a mother because that's what a real mother would do: stop the nonsense and not feel guilty about it.

Coming back to your own motherhood have you thought about how you're going to juggle it with your career? Or will it be very much a learning curve?

Absolutely. But where there's a will there's a way... women have done it for centuries, so I'm sure I'll be able to do it and find a way to balance it all.

Things We Lost In The Fire opens in UK cinemas on Friday 1st February 2008.