Doctor Who fans left reeling by series 12 finale's huge twists

The biggest reveal was that the Doctor herself is not actually from Gallifrey after all, but a mysterious being of unknown origin.

The ability to regenerate is something that was once unique to her, but the Time Lords spliced their genetics with her to gain this handy skill themselves.

All these revelations allowed for the addition of several other Doctors to the show's official canon, including those briefly glimpsed in the fan favourite story The Brain of Morbius.

Needless to say, the episode got fans talking...

Twitter user @sisterhood_karn was thrilled that the "Who" of the show's title made sense again after years of big reveals regarding the Doctor's identity.

Meanwhile, @shes_biochem pointed out that this was far from the first time that Doctor Who has changed its own mythology...

The Cybermen made their return in the finale, this time more threatening than ever before as they too gained the ability to regenerate thanks to some tinkering by The Master.

The episode left things on a major cliffhanger, as the Master was left (possibly) dead and the Doctor was incarcerated by the Judoon on an asteroid prison in the far reaches of space.

Generally, fan reaction seems to have been positive, but inevitably when such sweeping changes are made, some viewers aren't going to be too pleased.

Doctor Who will return in an episode titled Revolution of the Daleks, which is expected to air during the festive period at the end of the year.

Doctor Who is available to stream on BBC iPlayer