Are you beaming about Sunshine?

I'm thrilled with it. It's my kind of movie—proper science-fiction that looks like it cost an absurd amount of money and is also very smart.

Must be weird making a film where half of it's added in later…

It was my first time being involved in that kind of thing. It took a long time, but if anyone can maintain enthusiasm on set it's Danny Boyle!

It's your second gig with Danny and Andrew Macdonald—do you feel proprietorial?

[laughs] No, I don't think anyone can tell them—or Alex—what to do. But 28 Days Later… was huge in terms of what I learnt and what it did for my career.

So what was the deal-maker for you—working with Danny again or doing sci-fi?

It was one of the best scripts I'd read in a long time. And I thought it would be interesting to see what Danny could do with the genre.

There was originally going to be some rumpy between you and Rose Byrne's character…

We talked about it and it just didn't seem like the time or place, given their mission. We talked about it in 28 Days Later… too—would you have time for shagging when it's the end of the world?

What was it like liking with the other actors during rehearsals?

Great. We all had our own bedrooms, but we shared a bathroom and cooking area. It was all pretty basic, but we had fun.

Danny made you watch sci-fi movies like Alien and 2001 as research…

He also made us watch The Wages of Fear, which was brilliant. The intensity of that film and what it does with the characters' relationships—it was very, very helpful.

You spent time hanging out with scientists – was that as fun as it sounds?

They're incredibly serious in their work because it's all about finding out why? Why are we here? What's it all about? There's a level of arrogance, but not one that's unpleasant. It's quite endearing.

You've just done a comedy with Lucy Liu called Watching the Detectives…

Sunshine was intense—lots of bleeding and dying—so I decided to do a little comedy, goof around. But now I'm ready to do some bleeding and dying again…