Buster Keaton

Buster Keaton (1895-1966) was a famous silent film star of the 1920s. He was on the backlot of Archie Maplin's production company the day Leo Miller and Maximillian Love, two Terronite criminals, were apprehended by the Doctor. He aided an unknown cameraman in capturing much of the chase on film. (IDW: Silver Scream)

Behind the scenes
The cameraman refers to Keaton's last independent silent film, 1928's Steamboat Bill, Jr. as they film, referencing the Doctor and Maplin surviving a building facade falling on top of them due to a well-placed window, a gag that is used in that film. Keaton is afforded a named cameo, unlike fellow star Charlie Chaplin, whom IDW was not able to negotiate the rights to use as the protagonist of the story arc.