If it's just screaming - and I know this sounds so ridiculous - that gets old. But sometimes when there's literal chaos, it's like being in a war zone, and that's kind of exciting. You're just running through the crowd of people chasing after you and no one knows what's going on.

What worries me the most is that I don't know when my patience will run out, when I'll finally do something really stupid. Wait and see...

It happened while I was filming “Water for Elephants in which my partner is Reese Witherspoon. We had a scene with elephants but there were so many paparazzi around that it was scaring the animals and it was impossible to film. Out of the blue, fans, that were waiting for autographs, had enough and circled around the paparazzi. Teens made big guys run away. It was unreal! I was pleased.

I was really unfit last year, so I worked out for a long time, then spent time by myself in Oregon. For about two months the only person I saw was my trainer. Every day I did a lot of running and I just didn’t want to talk to anyone for two months. So when I started talking again, it was like you would communicate wrongly, like you wouldn’t really remember how to speak. That was one of the key things as well as just reading the book, reading the script a million times, just figuring things out.

I guess I had to learn how to run properly. I spent a lot of time on a giant treadmill, like one of those wheels mice run around on, and got filmed doing it to improve my form.