“It’s always down to whether there’s a good story. My immediate instinct was that story’s probably done. Not that we saw all of it, but I never thought we should see all of it. I’m slightly tempted, because I imagine Peter Capaldi and Alex Kingston would be absolutely hilarious together…”This could also depend on when Moffat chooses to leave and whether or not he will be completely leaving Doctor Who, or just stepping down as the show-runner.
"She could certainly have met other Doctors. So there’s nothing stopping us… But is there anything new we can do? Or is the new thing that Peter Capaldi and Alex Kingston would be very sexy together? Is that enough? We’ve always had fun with the fact that they don’t look like a couple.”
“Peter Capaldi and Alex Kingston would look like a couple – that’s the thing. Whereas I thought Matt and Alex were gorgeous together, but it looked slightly strange, because he was so much younger. Alex is just great fun to have on the show. It’s when you want to throw the Doctor a bit, because what River does so well is to make him a bit on the back foot and a bit flustered.”