Growing up, I really looked up to the classic Hollywood actors like Spencer Tracy, Robert Mitchum, and Peter Falk. I love character actors - I've never wanted to be the leading guy.

Back in 2005, the Anthony Nolan Trust could have asked me just to speak out about the lack of ethnic minority donors on the bone marrow register, but that would have meant nothing if I wasn't prepared to join up myself.

I'm very, very used to feeling anonymous, you know?

We've yet to deal with the uncomfortable history of England being involved in the transatlantic slave trade, whereas America has at least made some movies dealing with its racial history.

There are countless fantastic actors out there who are being denied the opportunity to play Broadway because they're not a name, and I think that's kind of wrong.

I grew up in an environment in Birmingham that was really multicultural, with black kids, Irish kids, Indian kids.

I loved working with Mandy Patinkin, I have to say.

You have to have a certain single-mindedness if you want to reach the top of the profession, and I'm not sure if I've got that cold-eyed egomania that perhaps is needed to get to the top. So as long as I can keep paying the mortgage and keep myself interested, I'll be happy.

If you're black and have leukemia, the chances of finding a donor are drastically reduced. I added my name to the register, and lo and behold, six months later, I was asked to donate. I had a week of 'conditioning' where I had to take these pills and injections to create new stem cells in my body.

I'm very fortunate. I loved school and, when I went there, race, gangs and violence were not issues. There was a feeling, gone now, that you had to be presentable. If you hadn't combed your hair, older black ladies - complete strangers - would come up to you in the street and pull out a comb and straighten your tie.

I've done so much different stuff, people kinda go, 'Do you live in Islington?' 'Did you used to go to so and so school?' And when I say I'm an actor, they don't believe me!

I hope my kids can experience the seasons and a climate that's sustainable. The idea that things are going to be so very different for them is slightly scary.

British people are surprised that I'm British!

We have a generation of black actors playing leading roles on film and TV - Idris Elba, Chiwetel Ejiofor - which is great and is breaking the mould.

I've been acting for 27 years, and anonymity has always been a part of what I do. Of course you get recognised every now and again, but 'Homeland' pushed me into a completely different strata, and that took me by surprise.

I've been on 'Mastermind' - I tied for first place and then lost on the number of passes. My subject was the 'His Dark Materials' trilogy by Philip Pullman. If I did it again, I'd choose Shakespearian tragedies.

I always get this feeling on my last day of work that I'm never going to work again.

When my agent told me I had an audition for 'Friar Tuck,' I burst out laughing. It actually brought a bit of sunshine to my day. I was thinking: fat suit. I was thinking: shaving my head. It was so outlandish, such a crazy idea.

It would be extraordinary if the BBC were to make me the first black 'Doctor Who;' it would be extraordinary.

I love the stage, but it doesn't pay the mortgage.

Art is all about the experience. I could say I don't really relate to opera, but then you watch Placido Domingo, and you go, 'Blimey, look at that.'

I remember when I first came to Los Angeles being staggered by the range of roles open to me. These were leading parts in shiny new projects, and what always excited me was knowing there was a possibility that I could actually get these parts. I always had the impression that I had a chance.

Before recording my 'Homeland' audition on my iPhone in my bedroom in Streatham, I hadn't worked or had an audition in the U.K. for nine months.

American television, for all its faults, still has a black presence in shows and even in commercials. You'll see black people in automobile ads, black women starring on their own television shows. We don't see that on British television.

Before 'Homeland,' I had £80 in the bank and no idea what I was going to do. I seriously considered giving it all up and getting a job as a lorry driver.

In England, you feel like a member of the revolutionary guard the minute you even mention race. But I do think that the OscarsSoWhite phenomenon will have to reflect back on England. What people are essentially saying is that they want to see more diverse stories. It's not about putting three black people in the back of the shot.

Studio heads seem to be getting the message that there is not only an audience out there, but there is a desire for people to see people of colour in central roles and in authoritative roles.

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

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.

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.

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.

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.

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

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.

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.

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

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.

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.

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.

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 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.

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 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 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.

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.

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

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.

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

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

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.