Doctor Who could find himself facing another gladiatorial task when he takes a trip back in time to the Roman Empire in the latest series. The Time Lord, played by David Tennant, and his new companion Donna, comedian Catherine Tate, arrive in Pompeii in AD 79, on the eve of the eruption of Mount Vesuvius. They are faced with the tough decision of rescuing the city's residents or leaving them to fend for themselves. The Thick of It star Peter Capaldi guest stars as banker Caecilius. The episode was filmed inside Rome's Cinecittà Studios, transformed to look like Pompeii.