I always found the extraordinary loss of life in the First World War very moving. I remember learning about it as a very young child, as an eight- or nine-year-old, asking my teachers what poppies were for. Every year the teachers would suddenly wear these red paper flowers in their lapels, and I would say 'What does that mean?'

Heath Ledger's performance in 'The Dark Knight' quite simply changed the game. He raised the bar not just for actors in superhero films, but young actors everywhere; for me. His performance was dark, anarchic, dizzying, free, and totally, thrillingly, dangerous.

It's like playing tennis, you play a different rally with different people. Every actor is different and the chemistry between actors is different.

I'm an eternal realist and the success rate for being an actor is pretty low.