I honestly haven't the faintest clue. Steven Moffat most definitely has taken it too far, this time. Grrrrrrrrrrrrrrrrrrrrrrrr!!!!!!!!!!!!!! I bet he has yet another trick up his sleeve. But for now, we have to set aside our perplexity and ponder on...
The actress could come back as another character.
If you remember just before David Tennent's Doctor had to fight the Cyberman who came through the hole opened by Torchwood. There was a black female tech. She was turned into a cyberman and died. The next season the same actress was the new companion Martha. She told the Doctor that her cousin had worked in the building that had housed torchwood.
I'm sure however it happens, it will make sense.
posted over a year ago
I'd say unlikely but happened before. Amy was once the soothsayer from "Fires of Pompeii".
There are plenty of ways. It's Doctor Who for goodness sakes! Anyway, the most basic way I can think of is that he meets her at an earlier point in her original time, whether by epic coincidence or by epic importance (hello Nobles and Mott), and then they go fizz away the "she's-a-dalek" universe of her (hello Amy and 36-year-crazy-Amy) and/or keep the Alaska from crashing... oh, blimey, never mind (massive paradox).