Reinette: Oh, Doctor. So lonely. So very, very alone.

Doctor: What do you mean, alone? You’ve never been alone in your life. When did you start calling me Doctor?

Reinette: Such a lonely little boy. Lonely then and lonelier now. How can you bear it?

Doctor: How did you do that?

Reinette: A door once opened may be stepped through in either direction. Oh, Doctor. My lonely Doctor. Doctor. Doctor who? It’s more than just a secret, isn’t it?

From Doctor Who – Season 2 Episode 4: ‘The Girl in the Fireplace’ (2×04) | Produced by BBC