I have no interest in Twitter or Twotter or Twatter. It would never occur to me to use it. People who Tweet during programmes are always asking, 'What happened then?' If you're bloody Twittering away all the time, you miss what is actually going on.

I used to read comics as a kid, and now I'm reading them for research. It's great fun. It's not bad homework.

On 'Supergirl,' there are huge characters with huge mythologies behind them. What's important is that you don't lock yourself into something.

When filming for 'Beowulf,' we were close to Hadrian's Wall; there was no phone signal, and the scenery was spectacular.

As soon as you become of interest to the media, the charity requests start rolling in, and it's not easy saying no. But if you endorse every charity that asks you, you're not really endorsing any of them. It has to mean something.

People come up and say very nice things about my work, like, 'You were great in 'Blood Diamond!'

To be on set with Tom Hiddlestone and Hugh Laurie is just fantastic. But during 'Homeland,' I was on set with Claire Danes and Damian Lewis, so I'm used to working with big hitters.

The idea that American producers and directors are choosing black British talent to save themselves a buck or two is ridiculous - it's because we're damn good.

I was lucky to get into drama school and become a professional actor. No-one ever mentioned the colour of my skin. It's only when I came out of RADA - the Royal Academy of Dramatic Art - that I suddenly realised people started to refer to me as a black actor.

The idea that people are watching me now is a bit unnerving, but I suppose it comes with the territory. It is, perhaps, the modern side of celebrity.

I was always the classroom clown, and the teachers allowed me a certain latitude. The assemblies were good, and the headmaster used to tell little stories; I loved the idea of communal storytelling.

It's been interesting seeing how vulnerable Obama is: not the secure president I thought he was or the strong leader that many people hoped he would be. He's a conciliator. But I've been listening to the Republican primary debates, and they're a bunch of lunatics. Just crazy.

I like America; I enjoy being there. Some people can't stand the insincerity - I love the waiter asking me how my day has been, the can-do culture there. I love the fact that again, you are visible in America. You turn the TV on, there are black politicians, black policemen, black soldiers.

If you don't register to vote, politicians don't really care about you: politicians aren't really caring about what you have to say, what you have to do, anything.

After 'Homeland,' I was offered a lot of very authoritarian, square, angry boss types, but I wanted to do something different. Casting directors are surprised when they look at my CV and see all the work I've done, from Shakespeare to playing Nelson Mandela.

We all have insecurities, but some of us are better at covering them up.

My black hero is and always will be Martin Luther King, not just because of the strength of his oratory but because his vision was very much the reality that I'd come to take for granted.

I watched the night unfold from beginning to end on my own here in my flat in Budapest where I've been working for the last six months, and when it was announced that Barack Obama was indeed president-elect, I wept.

When I first played Othello, a reviewer absolutely slaughtered me.

We live in a world of strange priorities, where Kim Kardashian buying a Lamborghini creates international headlines, but children in Niger suffering from drought and children in Britain suffering from leukaemia go unnoticed.

Support for charities takes many forms. Some people give their money, some their spare time. I give my name and my voice. We give what we can to make a difference to the people and issues that matter to us. But what's most important, especially for celebrities, is giving our genuine commitment.

You always want to look your best at events like the Globes, Emmys, or Oscars. It's a part of the business that I am not particularly comfortable with. I would prefer to turn up in a pair of jeans and an old shirt, but it's all about image - the studio wants you to look your best.

You don't just win an Oscar because you're a great actor. You campaign for that Oscar: you engage with it; you go on the David Letterman show, and you do the interviews, and that's how you get out there.

Everyone in America thinks I'm American - and everyone in England seems to think I'm American.