Regeneration in Doctor Who was a device created to explain the recasting of the main character, the Doctor himself. But it's something all Time Lords are capable of, and occasionally we've seen Time Lords other than the Doctor regenerate on-screen. E.g. the Master has regenerated once on-screen, and an unknown number of times off-screen. My question is:

how many regeneration events, other than the Doctor's, have appeared on-screen?

Main canon only (as far as such a thing exists in Doctor Who): the TV series, Old and New, plus the McGann film.

  • 2
    An interesting example of a case where we should have seen regenerations but did not was The Deadly Assassin. A rather bizarre story; it establishes that Time Lords can regenerate 12 times but none of the Time Lords killed regenerate. The only story in classic Who without a companion. And a thoroughly redundant title; a non-deadly assassin would by definition not be an assassin. Aug 23, 2016 at 5:22
  • In "The Impossible Astronaut" the Doctor is shot twice and seemingly killed.
    – user66716
    Aug 23, 2016 at 9:52

2 Answers 2


Not many

  • Although the actual regeneration isn't shown on-screen, in "Planet of the Spiders" we see that the Doctor's old mentor K'anpo Rimpoche has regenerated into Cho-Je, a character introduced earlier in the story1, 2
  • In "Destiny of the Daleks", we see Romana "trying on" various regenerations, although the actual regenerative process is not shown on-screen, until she eventually settles on the body played by Lalla Ward:

  • The Master (Jacobi to Simm) in "Utopia"

  • Melody Pond to Mels in "Day of the Moon":

  • Mels to River Song in "Let's Kill Hitler"

  • The Time Lord General in "Hell Bent"

  • A debateable one3, but K-9 sort-of regenerates (it's referred to as being caused by a "regeneration unit") in the first episode of his 2009 series:

Finally, though not really a regeneration, it seems worth mentioning that we see the Master taking over a new body in "The Keeper of Traken":

1 Wibbly-wobbly...

2 Nod to Elliot Frisch for reminding me of this one in comments.

3 As John Sensebe points out in comments, K-9 isn't a BBC-licensed show, so it occupies a weird canon-space. I'm inclined to leave it, though, mainly because I think it's funny.

  • @ElliottFrisch As I recall, only the Doctor actually regenerates in that one. Also, Fatal Death isn't usually considered "canon" (with the normal Doctor Who canonicity disclaimers) Aug 23, 2016 at 0:52
  • True. Planet of the Spiders. K'anpo / Cho-Je. Aug 23, 2016 at 0:57
  • @ElliottFrisch Ah yes, forgot about that one; the actual regeneration isn't shown on-screen, but it's at least as fair as Romana's, so I'll add it in Aug 23, 2016 at 1:07
  • The K-9 series isn't canon, so that one is very debatable. You're missing the regeneration of K’anpo in "Planet of the Spiders", which is special since that was the first time the word "regeneration" was used to describe the process. It's also a pretty weird one, for spoilerish reasons. Aug 23, 2016 at 1:09
  • No worries; regeneration was seldom seen & "mysterious". Maybe The Watcher from Logopolis deserves a mention too? Also, the Minyans of Minyos in Underworld. Aug 23, 2016 at 1:09

If you only count on-screen regenerations, there have been five:

  • River song regenerates twice, in "Day of the Moon" and "Let's Kill Hitler"
  • The Master regenerates on-screen once, in "Utopia"
  • An anonymous guard regenerates in "Hell Bent"
  • In classic Who, a Time Lord named Azmael commits suidice by regeneration in "The Twin Dilemma". (This one is debatable -- he doesn't actually regenerate, he dies by forcing a regeneration when he has none left.)

We know the Master regenerated several other times, but not on-screen. Romana also shows up in a number of forms, but the regenerations always happen off-screen.

Also of note, as of "Day of the Doctor", we have seen all of The Doctor's regenerations on-screen. The regeneration sequence from Eight -> War -> Nine was originally not shown, but "Day of the Doctor" and "Night of the Doctor" fill that gap.

  • 1
    We haven't actually seen the regeneration from Troughton to Pertwee, especially if you believe in Season 6b. Aug 23, 2016 at 1:25
  • @JohnSensebe Interesting, I didn't hear about that before...
    – Zommuter
    Aug 23, 2016 at 5:53
  • 1
    Does Jenny in 'The Doctors Daughter' count as regeneration?
    – sueelleker
    Aug 23, 2016 at 5:55
  • On the DVD of "The War Games", one of the special features is an excerpt of a fan-made film called "Devious" which does show the regeneration from Troughton to Pertwee, via an "interim" Doctor played by Tony Garner. Filming began in 1991 after Troughton was dead, so they used stock (colour) footage of him (I think taken from "The Two Doctors"), but the Garner-to-Pertwee sequence was filmed in 1995 and Jon Pertwee actually appeared in the film, not just in stock footage. It was his last performance as the Doctor before he died the following year.
    – Wallnut
    Aug 23, 2016 at 8:31

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