As we ponder just who Billie Piper could be playing now (oh, we have theories ), below, we take a look at 10 episodes (all streaming on HBO Max) you should watch now that she’s back on Doctor Who. This episode and one word (“Run”) are what started it all.

David Tennant and Billie Piper are gearing up to star together again in Doctor Who for a special anniversary episode after 17 years.The Harry Potter alum played

Ncuti Gatwa's Doctor Who exit brought back a familiar face to the TARDIS, but didn't explain how and why Billie Piper returned to the show.