To act with a tennis ball and imagine it's a tentacle, or if you're in some kind of wilderness film and you go, 'Okay, we can't have a grizzly bear here, but imagine when you step over the rock there there's a grizzly bear.' I don't know. They're tough moments.

There's the pressure of being a No. 1 on the call sheet, being a lead actor. There's almost this feeling like being captain of the team. You want to put a bit of energy into actually setting a good example.

I have a lot of ideas that I feel are half-formed, or half-way okay.

It feels good to be fit and strong.

Whenever you deal with science fiction you are setting up a world of rules. I think you work hard to establish the rules. And you also have to work even harder to maintain those rules, and within that find excitement and unpredictability and all that stuff.

The biggest difference for me is momentum. On a smaller film you get to shoot sometimes four or five scenes a day and you've got to do the tight schedule. I think I really feel the luxuries of a big budget film.

Everything is a learning process: any time you fall over, it's just teaching you to stand up the next time.