I was fascinated by the world. I thought, "I just want to be a part of this world."

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.

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

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.

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.

When you read something that good, it's terrifying because you're thinking, "Oh, god, what if I don't get this?"

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