"When I'm given a role, the first thing I do is read the play over and over again. I scour the script and write down everything the character says about himself and everything that everyone else says about him. I immerse myself in my character and imagine what it might be like to be that person. When I played Cassio in Othello I imagined what it would be like to be a lieutenant in the Venetian navy in 1604. I sat down with Ewan McGregor and Chiwetel Ejiofor and together we decided that Othello, Iago and Cassio had soldiery in their bones. I took from the script that Cassio was talented and ambitious, with no emotional or physical guard - and that's how I played the part. For me, acting is about recreating the circumstances that would make me feel how my character is feeling. In the dressing room, I practise recreating those circumstances in my head and I try to not get in the way of myself. For example, in act two of Othello, when Cassio is manipulated to fight Roderigo and loses his rank, some nights I would burst into tears; other nights I wouldn't but I would still feel the same emotion, night after night. Just as in life, the way we respond to catastrophe or death will be different every time because the process is unconscious. By comparison, in Chekhov's Ivanov I played the young doctor, Lvov. Lvov was described as "a prig and a bigot ... uprightness in boots ... tiresome ... completely sincere". His emotions were locked away. I worked around the key phrase: "Forgive me, I'm going to tell you plainly." I practised speaking gravely and sincerely without emotion and I actually noticed how that carried over into my personal life: when I played the open-hearted Cassio, I felt really free; when I played the pent-up Lvov, I felt a real need to release myself from the shackles of that character.