In 2014, Tom Baker revealed that he had agreed to reprise his role as the Fourth Doctor for an episode, before Elisabeth Sladen died.
Most characters call the journalist Sarah Jane, but she was called Sarah in the original Doctor Who (1963). The Doctor notes that she allows a few close friends (such as him) to call her Sarah.
CBBC originally approached Russell T. Davies asking for a Doctor Who spin-off involving a young Doctor on Gallifrey. Davies rejected the idea, feeling it would take away from the "mystery" of The Doctor, and proposed this series after a positive experience working with Elisabeth Sladen in School Reunion (2006).
Eight of the cast have appeared in the original Doctor Who (1963): Elisabeth Sladen, John Leeson, Nicholas Courtney, Katy Manning and four season three actors Brian Miller, Zienia Merton, Jeff Rawle and Donald Sumpter.
Brian Miller, Elisabeth Sladen's husband, played Harry in The Mad Woman in the Attic: Part One (2009)/The Mad Woman in the Attic: Part Two (2009).