WARNING: The following post contains SPOILERS for the season 7 finale of Doctor Who. If you are not caught up on the show, proceed with caution.

It’s been nearly half a century since Doctor Who first aired on November 23, 1963 – with William Hartnell kicking-off the now iconic series as the first incarnation of The Doctor. Fifty years later and the BBC is preparing to celebrate the two-hearted time-traveling alien with the 50th Anniversary multi-doctor mash-up special “The Day of the Doctor” – featuring current leads Matt Smith and Jenna Louise-Coleman, the return of series favorites David Tennant and Billie Piper, along with John Hurt as a previously unidentified regeneration of The Doctor.

Mystery has surrounded Hurt’s position in the Doctor Who mythology ever since he was teased at the end of the season 7 finale, “The Name of the Doctor” – when his character was identified only as “The Doctor.” Now, thanks to a surprisingly forthcoming (and controversial) 50th Anniversary prequel minisode, we have a much clearer picture of where Hurt’s Doctor fits into the Time Lord’s story.

A month back, show runner Steven Moffat asserted that, on the subject of The Doctor’s regenerations, fans should “go back to your DVDs and count correctly this time. There’s something you’ve all missed.” In our write-up we speculated that Moffat was teasing that, since viewers never saw the regeneration from the Eighth Doctor (Paul McGann) into the Ninth Doctor (Christopher Eccleston), it was possible at least one more iteration of The Doctor could have existed offscreen.

Thanks to the prequel minisode, we now know this speculation to be correct, as Moffat brought McGann back for another dose of Doctor duty, and to set the stage for Hurt’s redacted incarnation of the Gallifreyan. The minisode also attempts to explain the stakes that will ultimately lead to The Doctor’s darkest chapter, the one that can be summed up from Hurt’s statement in the season 7 finale: “What I did, I did without choice. In the name of peace and sanity.

In the minisode, we see the Eighth Doctor overcome with grief and frustration at the consequences of the Time War – as the ongoing Dalek/Time Lord conflict has grave ramifications throughout the universe. The situation had become so bleak, and the Time Lords so notorious, that Cass (Emma Campbell-Jones), a crew member trapped aboard a doomed spaceship, would rather die than be saved by The Doctor. Cass’ fate serves as the final straw for The Doctor and, upon her death, he accepts an invitation from the Sisterhood of Karn to choose the type of person he’ll be after his next regeneration. Overcome with anger, The Doctor chooses to become a warrior – ushering in his regeneration as “The War Doctor” (John Hurt).

Check out new images from the 50th Anniversary Special “The Day of the Doctor” below along with a few from “The Night of the Doctor” prequel (click to enlarge):

While the minisode does an excellent job of teasing what’s to come in the 50th Anniversary Special, as well revealing the endpoint for McGann’s Doctor, it also threw a few significant sticking points into long-running Doctor Who canon, especially for fans of the Eighth Doctor Big Finish audio dramas and with regard to the Flame of Eternal Life (previously seen in “The Brain Of Morbius”) – which, according to Moffat, could allow McGann to regenerate into a woman (paving the way for a female Doctor down the line).

However, one big question remains: will Christopher Eccleston (who previously stated he would not return) actually have a surprise cameo in the 50th Anniversary Special, assuming The War Doctor regenerates, closing the offscreen regeneration loop or will Moffat leave the gap open for other future story (and pre-Ninth Doctor) possibilities? To answer that question, fans will no doubt bring up the thirteen regeneration limit but, as we all know, Moffat will, or already has (depending on how you feel about a few key canon moments), provided room for many more regenerations to come – as the old series itself has done many times over with other Time Lords.

We’ll keep you up to date as we hear more, but in the meantime, check out our Doctor Who Viewing Guide: Tips, Suggestions & Complete Episode List.

Matt Smith will return as Doctor Who on November 23rd for the 50th Anniversary Special – followed by the 2013 Christmas Special on December 25th.

Follow me on Twitter @benkendrick for further updates on Doctor Who as well as future movie, TV, and gaming news.