Ideally this will be about the first appearance of an actor in their first film - like the director basically saying, this person is going to be a star, look at this shit - but we can talk about debuts and first reveals more generally if you like.

For me, it has to be Cameron Diaz in The Mask, walking into the office, camera panning up the black and white dress - that's how you kick off a career.

Somewhere on the Guardian was talking about Robert de Niro in Mean Streets as the best first moment of an actor, but I haven't seen it.