One of the most, in a weird way, encouraging things a director can say to an actor - I know this as an actor - is when you ask them a question, they say, I don't know - 'cause it means there's some space there for you to find out. And it means that there's going to be a process.
Three children have become adults since a phone call with Jo Rowling, containing one small clue, persuaded me that there was more to Snape than an unchanging costume, and that even though only three of the books were out at that time, she held the entire massive but delicate narrative in the surest of hands.
Acting is about giving something away, handing yourself over to whatever role you are asked to play. I'm not hiding or escaping or seeking anonymity. I reserve the right not to have a rubber stamp on my forehead saying this is who I am. Because who I am gets in the way of people looking innocently at the parts I play.