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.

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.

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.

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.

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 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.

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.

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

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

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.

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

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'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.

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.

British people are surprised that I'm British!

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.

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'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.

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.

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.