Goodbye Ncuti Gatwa: Billie Piper returns to Doctor Who in landmark regeneration

Doctor Who closes its 15th season with an unexpected regeneration.

Update: Jun 1st, 2025 06:59 CEST

Season 15 of Doctor Who ended with a surprise we didn’t see coming: the Fifteenth Doctor, played by Ncuti Gatwa, underwent a surprise regeneration. However, the real surprise is seeing the familiar face of the Doctor in future seasons.

Warning: Major spoilers ahead for Doctor Who episode The Reality War.

The Reality War introduces a familiar face to fans but a new one to the Doctor

Billie Piper, whom we met as Rose Tyler in the 2005 revival of Doctor Who, made a surprise appearance in the final minutes of the season finale, “The Reality War.” In the episode, the Doctor, Belinda Chandra (Varada Sethu), and Ruby Sunday (Millie Gibson) take on the “Holy Trinity” of the Ranis (Archie Panjabi and Anita Dobson), Conrad Clark (Jonah Hauer-King), and Omega in a fight for reality itself.

The Fifteenth Doctor used up his regeneration energy to save Poppy after she vanished into the post-Wish World reality. He finally returned to the TARDIS to complete his regeneration in front of Joy (Nicola Coughlan), whom we saw in the Christmas special, ‘Joy to the World.’

However, the question remains whether she will be referred to as the Sixteenth Doctor since the credits only mention her as “Introducing Billie Piper.” We will have to wait and see.

“It’s no secret how much I love this show, and I have always said I would love to return to the Whoniverse, as I have some of my best memories there,” Piper said in a press release from the BBC. “So to be given the opportunity to step back on that TARDIS one more time was just something I couldn’t refuse, but who, how, why, and when, you’ll just have to wait and see.”

This marks a lot of first in the 62-year-old series. This is the first time in the show’s history that a Doctor regenerates without a successor having been announced beforehand. It is also the first time that a former companion returns to portray the Doctor, that’s a lot of Timey-Wimey. Conversely, Gatwa’s tenure was brief, lasting only two seasons, making it one of the shortest since Christopher Eccleston revived the series as the Tenth Doctor.