Meanwhile back to the game changing, 7th episode (or the series 777th episode if you like), it seems that Dorium, the alien from The Pandorica Opens that River acquired a vortex manipulator off is back in the mix. He's not also the only thing returning as both Cybermen and Sontarans (Dan Starkey playing a character called Strax) will be appearing in this episode as well. Other casting for episode 7 include Annabel Cleare and her son, Henry in two undisclosed roles, Lydia Fewell as Child Alien, Dan Johnston as Thin Man and Charlie Baker as Fat Man. This episode is directed by Peter Hoar.
There's also been some recent speculation on Twitter that Gareth Roberts could be writing an upcoming episode and Toby Whithouse has been confirmed for an episode as well, which means nearly all the writers for the season have been announced. Episode 7 is also due to heavily twin babies as well, which could add more fuel to the fire about Amy/Rory being River's parents. It's the current popularity theory in regards to River's identity being bandied about the place, despite no concrete proof yet to support it.