(but one).

While we now know that River Song (Alex Kingston) is Melody Pond—the daughter of the Doctor's (Matt Smith) companions Amy (Karen Gillan) and Rory (Arthur Darvill)—we don't know exactly just who she is to the Doctor yet. Speaking to Total TV magazine, Moffat revealed that the upcoming season-six finale, ''The Wedding of River Song,'' will go a long way in shedding some much-needed light:

"[It] is probably the maddest Doctor Who story ever. But it answers pretty much all the questions about what we saw in 'The Impossible Astronaut.'

"We kind-of know who River Song is, but we don't, because no one has been asking who her parents were. And the big question is, who is she to the Doctor? She seems to behave like a wife or lover. How is that possible?

"This is where we reveal what it's all about. So you do get answers to all the questions — except for one, because that's the way I am."

In the past few episodes, we've been told that the Oldest Question in the Universe will be asked, and then Silence will fall. We don't know about you guys, but our money's on that question being something like "Just Who is the Doctor?" or "What is his true name?" Which, in turn, will lead to our Time Lord finally making the big reveal to River—which we know she knows from the season-four episode ''Forest of the Dead.''

Or, knowing Moffat, it could be as simple as: ''Will you marry me?'' The episode is called ''The Wedding of River Song,'' after all. But what do you guys think? And, most importantly, which question do you think Moffat won't answer just yet?

The Doctor Who season-six finale airs this saturday on BBC One, BBC America and Space.

Maybe we'll finally find out why there are no ducks in the duck pond.