The Fourth Dimension
The Girl in the Fireplace
Two horses played Arthur in the episode: one named Bolero was used for close-ups on the spaceship, and another, actually named Arthur, for the scene where the Doctor jumps through the time window.
According to writer Steven Moffat, the clockwork droids were inspired by The Turk, a chess-playing automaton of the period which was subsequently revealed to be a hoax.
This episode won the 2007 Hugo Award for Best Dramatic Presentation, Short Form.
The real Madame De Pompadour was apparently nicknamed "Reinette" by her mother after a fortune teller claimed that she would someday 'reign' over the heart of a king.