The last time "Doctor Who" fans saw Alex Kingston's River Song, she was but a shell of her former self. (Literally. She was downloaded into a library computer, then summoned to save the Doctor in "The Name of the Doctor.")

But since time travel works in timey-wimey ways, River will return for this year's Christmas special, for her first-ever meeting with Peter Capaldi's Twelfth 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," Kingston told BBC. "Steven Moffat is on glittering form, giving us an episode filled with humour 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!"

It will definitely be interesting for fans to see how River's relationship with Twelve fits into their respective timelines. River and the Doctor have always had their timelines reversed, with River meeting the Eleventh Doctor for the first time during his later years -- when he knew everything about her -- then moving backwards, until she finally met the Tenth Doctor (who had never met her in his timeline) in "Silence in the Library."

Twelve should clearly know all about River and recall all of their memories together when they meet again this Christmas, but the question is, will she know anything about him when their timelines cross again? And Twelve, being the warm and fuzzy teddy bear that he is, will he even care?

"Another Christmas, another special for 'Doctor Who' -- and what could be more special than the return of Alex Kingston as Professor River Song?" Moffat said. "The last time the Doctor saw her she was a ghost. The first time he met her, she died. So how can he be seeing her again? As ever, with the most complicated relationship in the universe, it’s a matter of time..."

Curiously enough, BBC's announcement about the Christmas special did not once mention the Doctor's current companion, Clara Oswald (Jenna Coleman), which will surely add to even more speculation about her continued presence on the show.

But what do you think about all this, sweeties?