Question: What English comedian, screenwriter, actor and singer is a companion of the Twelfth Doctor in the "Doctor Who" series?
Sentence (from "Nardole"): He initially appeared in the 2015 Christmas special "The Husbands of River Song" as a companion of River Song, before returning in the following episode "The Return of Doctor Mysterio", having become the Doctor's companion in the meantime.
Relevant evidence: No