In the latest issue of DWM, Steven Moffat may have dropped some interesting hints on what we can expect from Matt Smith’s final episode this Christmas.

Asked about how the TARDIS exploded back in Series 5, he says:

“Oh, never mind the TARDIS blowing up, what about the endless, bitter war Kovarian was on about? And what’s Trenzalore? And the oldest question in the universe? And what exactly do they mean, silence will fall? Anyway, I’m off to a readthrough…”

The readthrough in question being the Christmas episode currently filming.

[Big thanks to Finlay for the tip!]