With "Doctor Who" Season 9 nearly over, it's time to look forward to the annual Christmas special and Season 10. For that, actor Peter Capaldi has a few spoilers, some of which River Song might not approve of.

During the first Doctor Who festival in London, Capaldi discussed Alex Kingston's upcoming appearance in the Christmas special as the fan-favorite River Song. Capaldi hinted that unlike her dynamic with the previous Doctors, this time there might be romance.

"Yes, there is [a chance for romance]," said Capaldi according to Radio Times. "I'm trying not to give it away. My Doctor is different from the Doctors who were there when Alex first arrived. This Doctor's different from that. It's a different dynamic."

Written by execute producer Steven Moffat and directed Douglas Mackinnon, even Kingston herself did not expect to return after her 2013 appearance in "The Name of the Doctor."

"To be honest, I did not know whether River would ever return to the show, but here she is, back with the Doctor for the Christmas special," said Kingston back in September.

"Steven Moffat is on glittering form, giving us an episode filled with humor and surprise guest castings. I met Peter for the first time at Monday's read through, we had a laugh, and I am now excited and ready to start filming with him and the Doctor Who team. Christmas in September? Why not!"

The Christmas special does not indicate what's to come in "Doctor Who" Season 10, however. Originally presumed to be a truncated season, the reports now are less certain on its schedule. However, Capaldi has been confirmed to be staying for at least another season.

"Next year's a different thing, and it's quite interesting and challenging, and scary," said Capaldi according to Doctor Who TV.

"I've only done two series, but I'm amazed at how fast it's gone. I've done 26 episodes now, you know. And every time you've got through a season, and you've discovered all these things about this new Doctor, it's sort of scrapped and you start again. You have to come to it afresh and find new things, but that's quite challenging and interesting. So I'm fascinated to know where we're going to go. Because in some ways he's much more amenable, but in other ways he's even darker. So I think that makes for a very interesting character."