It's a strange thing, but you get this click in your brain; the wonderful feeling that the entirety of a character is suddenly available and accessible to you.
I don't tend to offer up a critique unless I have a clearly formulated alternative, because there's nothing worse than people on a set or any kind of artistic life who critique something but who don't have anything to offer.
I had done a couple of auditions for 'Amistad' and didn't feel it was going to go any further - and then the call came about heading to Los Angeles to work with Steven Spielberg. It was surreal: exciting, challenging, overwhelming.
I wanted to be an actor ever since I got on stage for the first time, aged 13. Before that, I thought I might follow in the medical footsteps of my parents: my father was a doctor, my mother a pharmacist.
I've always been a believer in research. It's great to have an instinctual human reaction to a character, too, of course, but it has to be countered with knowledge and understanding.
I loved reading when I was young. I was just completely taken by stories. And I remember taking that into English literature at school and taking that into Shakespeare and finding that opened up a whole world of self-expression to me that I didn't have access to previously.
I was already devouring literature and I was the ripe old age of 15 when I decided to be an actor. I just thought plays were the most fantastic way of expressing life. I thought I'd discovered Shakespeare - 'hey, there's a new guy in town, don't know if anyone's read him.' I was just excited about the whole thing, from day one.
This is going to sound completely absurd, but I do sometimes feel like the enjoyment of an awards ceremony or the pride in the finished article hasn't ever surpassed the joy of doing the work, of making it. The doing it is really the bit I'm there for.
It's a weird thing when you spend your life trying to find these great scripts and great parts. You are reading scripts, you are traveling the world, you are hassling your agent. You are trying to find that script.
The inherited tradition is that we don't tell stories about slavery from the perspective of the slave. It's told through the president or the lawyer.
There's a catharsis in cutting down trees. But there's absolutely none of that in picking cotton. It's maddening! It's fiddly, and it pricks your fingers, and it's something that's a very hard skill if you have no alacrity for it.
We take it for granted sometimes that certain parts of our history are told, and we take it for granted that we know all that stuff, and we move forward along on that basis, but there are also massive gaps, and we have to try to address them.
The idea of making a film - a film that I had certainly never seen before - about the slave experience was a huge responsibility. It's a project that requires a wider understanding of the geopolitical nature of the slave trade, of historical and modern-day racism.
The history of slavery and the complication of slavery is that it is an international concept. It is something that affected people who were our people. For example, there were people from the west of Nigeria who were taken by the hundreds of thousands and brought to Louisiana. I'm Igbo; my family is Igbo. So it is a story that I'm connected to.
I enjoyed being in California for a while. But that's the thing about London: you can't really shake it. I've always had the impression when I was in L.A. for long periods of time that simultaneously my life was happening somewhere else, and I'm missing it.
David Mamet was great to work with. He was everything that I thought he would be as a director. He's incredibly articulate, an easy collaborator. Extraordinarily knowledgeable about film and writing.
Dividing everybody into genders and sexuality and races and religions, and I think it's important to have films out there, to have discussions out there which really try to get to grips with where that kind of thing can lead.
I became an actor by doing school plays and youth theaters, and then National Youth Theatre of Great Britain. And then I did study at the London Academy of Music and Dramatic Arts. For me that was a good way to enter the field, to work in the theater.
I didn't know anything about '12 Years a Slave.' Not the book, not Solomon Northup, which I was quite shocked by, once I'd read it, that it wasn't a seminal text. I think it deserves to be.
Depending on what your interest in theater is, I always recommend working on plays. It's a great way to be introduced to the field, and also a great way to be seen by agents and representation. I'm also a great advocate for studying acting at a drama school or a college.