Doctor Who Star Regenerates Into Billie Piper, But Fans Think She's Not Actually Playing The Doctor

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, and regenerate into a character played by former series regular Billie Piper.

But is Piper actually playing the Doctor? As the credits rolled, Gatwa (and the returning Jodie Whittaker, who popped up for a lovely cameo) were both credited as The Doctor. Piper was not. Instead, the credits simply noted "And introducing Billie Piper" to acknowledge her surprise reveal, without a role named.

Piper previously starred alongside Christoper Ecclestone's Ninth Doctor and David Tennant's Tenth Doctor as loyal companion/love interest Rose Tyler, who was last seen settling down with another version of Ten in a parallel universe.

But Piper also later returned as The Moment, a sentient weapon with a humanoid interface, which was key to the series' 50th anniversary episode The Day of the Doctor.

Of course, in previous years, an actor's regneration sequence has always been used to hand off from one lead actor playing the Doctor to the next. So, the surface implication here would obviously be that Ncuti Gatwa's Fifteenth Doctor has become Billie Piper's Sixteenth Doctor.

In-universe, regeneration is simply a process of renewal — while the Doctor's body and personality changes, they are still playing the same entity.

But the credits tease, the surprise casting of Billie Piper, and the reality of the show's current production status has fans wondering otherwise, especially after previous shenanigans around the series' last regeneration.

Remember, of course, that Gatwa's Doctor appeared through a new type of regeneration not seen before — bigeneration, allowing him and Tennant's Fourteenth Doctor to coexist. Have we just seen a new type of regeneration again, if Piper has not been officially confirmed as The Doctor?

"What if this is the next part of bigeneration," one fan wondered on reddit, "re-merging with 14 now 15 has finished their therapy, and the Rose/Bad Wolf is the final part that returns to 14 for the pair to become 16 freshly?"

And then there's the practicalities of the series' current production. The BBC has maintained that a decision to renew the show by itself and co-production partner Disney would only take place after the current season has ended. This has led to some confusion among fans and in the media over the show's future. Currently, no confirmation of a new season, or schedule for it to be filmed, has been laid out.

With Gatwa set on leaving and the show's future still to be announced, the BBC would have faced the option of casting the next Doctor without being able to confirm when (or if) they'd be needed to return. Alternatively, the show could have broken convention by not showing who Gatwa's Doctor regenerated into — though this would have likely only led to a greater question mark over the show's current status.

"I don't think the writers themselves know who Billie is playing. It seems like such a last moment decision to cast her that was only done to avoid having an open ended regeneration," another fan said. "So she could be The Doctor. She could also not be. I don't think they decided yet."