I wanted somebody that could bring a lot of authority, but that you could feel the weight of the world on his shoulders. When I watched Luther, that's the essence of the character. I was watching Luther and I was like this guy makes much more out of Luther. Luther is carrying literally the evils of the world on his shoulders. He's doing penance for all humanity. Idris is one of those actors that is capable of embodying humanity, in almost like a Rodin sculpture type of way, larger than life, almost like a Russian realism statue, big hands, all the turmoil of humanity in his eyes. I wanted somebody that you could have doubts internally, and very few guys can do that.