8 Doctor Who Fan Theories That Became Fact

Even though it's been around since the earliest days of the show, the rules of regeneration have never been explicitly defined. This has led to the long-running fan theory that, in some rare cases, Time Lords might actually be capable of regenerating into something different - something that isn't humanoid.

While the show has never strayed from its "Time Lords look like humans" stance, there is some slight evidence that supports the notion of a Time Lord-to-animal regeneration. Some fans point to the fact that the Doctor usually checks their body when they regenerate, often appearing relieved that they've got two arms, two legs, two eyes, and other humanoid features.

And then, there's the fact that the Master once looked like this - possibly as far away from a regular human as a Time Lord has ever appeared.

Still, without any sort of official confirmation or acknowledgement, this idea remained nothing more than a theory - until last year, that is.

Penned by former showrunner Russell T Davies - and featuring the voice of David Tennant - 2020 webcast The Secret Of Novice Hame confirmed that the Doctor has had "hundreds of faces and forms", including men, women... and animals.

For obvious reasons, we'll probably never see an animal version of the Doctor leading the show, but this does open the door for the likes of Big Finish and Titan Comics to tell all sorts of wacky stories. Dog-tor Woof, anyone?