Nicholas Courtney made his first appearance as Brigadier Lethbridge-Stewart since 1983's The Five Doctors, and Bessie appeared for the first time since that serial as well. Following Courtney's death in 2011, this serial marked his last televised performance as Lethbridge-Stewart in the series proper; that same year, his character was written out of the series in The Wedding of River Song out of respect for the actor's passing. However, Lethbridge-Stewart as a character would return to the series approximately three years later, making a minor appearance in Cyberman form near the end of Death in Heaven in a brief scene paying tribute to the late Courtney.