The Doctor (Doctor Who) footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist". In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being "The Three Doctors" (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering
An Adventure in Space and Time of 1960s Dalek props crossing the bridge, in a recreation of a famous scene from "The Dalek Invasion of Earth" (1964). Interior scenes replicating early "Doctor Who" production at Lime Grove Studios were also filmed, with replicas of early television equipment being used. A number of the cast have appeared in "Doctor Who" at one time or another, most notably original companions William Russell and Carole Ann Ford. David Bradley appeared in the Series 7 episode "Dinosaurs on a Spaceship", while Jessica Raine was in the Series 7 episode "Hide" and the "Call the Midwife" charity cross-over mini-episode; Jeff Rawle