Doctor Who star Ncuti Gatwa on setDoctor Who boss Russell T Davies has revealed that the upcoming season finale will clear up one mystery that’s been surrounding the show for the last few years.In 2023, Ncuti Gatwa’s Fifteenth Doctor took over at the helm of the Tardis in the long-running sci-fi series’ first ever “bi-generation”, in which he literally split from his predecessor, played by David Tennant.