Doctor Who star Ncuti Gatwa has quit the show and passed his Time Lord baton to Billie Piper — but fans believe all is not what it seems. This weekend's season finale saw Gatwa leave the BBC's big sci-fi show after 18 episodes in the title role,

The season finale of Doctor Who, ‘The Reality War,’ was shocking for many reasons. However, the biggest surprise involved an appearance by actress Billie Piper, who played Ninth and Tenth Doctor companion Rose Tyler.

Billie Piper made a triumphant return to Doctor Who over the weekend, in a season finale that gave fans more questions than answers. The Reality War episode ended on a universe shattering bombshell with Ncuti Gatwa regenerating and transforming into the former Rose Tyler actress.