 Russell T Davies, the series' executive producer, later noted that, due to MacDonald's work, the episode included some of "the most beautiful [visuals] we've ever had".British actress Carey Mulligan was chosen to play Sally Sparrow; Mulligan was reportedly ecstatic to have been cast in the series.She was initially concerned with the fact that Tennant would have little screen time, but after the episode aired was very pleased with the final result.