I had an outfit that was designed for minus 30 degrees, so I had to work with costume to strap ice packs all over me because I was boiling, even out on the glacier. I was constantly trying to unzip it and take off the hat. I was just sweating. I found it very hot.

Did it ever occur to you that there might be more than one alternative?

Sometimes you even start to sound like the character, because you're living and breathing them every day on the set. It gets into your bones, it becomes a part of you.

I think the benefit of being a writer is that I'm looking for the subtext on the page, because all good writing has subtext. And as a writer, you look at the big scope of things, the big story, rather than just your individual story line, because I think it's important to know what you're in and how you fit into it.

When you get out onto a glacier that's the size of Northern Ireland and it's so vast, and you're standing on top of it and you can see forever, it's so pure and clear that you can see for miles and miles and miles. You really do think, "Wow, there is a god!" You feel very humbled.

It's a real luxury to be able to develop with your character.

As a writer you see the big picture and how you can tell as one character, how your storyline is going to meet up with all these other storylines. And as an actor you're thinking of all the minutiae, all the very small details.