It was mentioned by the Eleventh Doctor in the episode of Sarah Jane Adventures titled 'Death of the Doctor'. The episode first aired back in October.
Edit:
Plus, I seem to recall something about the Time Lords giving the Master a new set of regenerations from somewhere, so there's probably something to that 'Time Lords regulated regenerations' idea.
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Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.
Edit:
Plus, I seem to recall something about the Time Lords giving the Master a new set of regenerations from somewhere, so there's probably something to that 'Time Lords regulated regenerations' idea.
-----
Stand between the Silver Crystal and the Golden Sea.
"Youngsters these days just have no appreciation for the magnificence of the legendary cucumber." --Krityan Elder, Tales of Vesperia.