The year after I started (in Eton), a drama teacher arrived called Simon Dormandy, and he treated us like professional actors. He had high expectations-you played women, you played old men, you were pushed outside your comfort zone. Everything you see about Eton from the outside is very structured: it's hierarchy and order, all uniforms and collars. But Simon encouraged freedom and playfulness and allowed you the room to make mistakes. Most importantly, for me, he taught us how to speak verse. I did Henry VI and Richard III there, and I suppose that's where it all began. In 2002, when I was still at Cambridge and Mark Rylance was putting on the 400th anniversary of Twelfth Night at Middle Temple Hall, the casting director from the Globe asked Simon if he knew any young actors who might play Viola. I auditioned and got the part.