I've met you before?
Professor River Song: You're doing a very good job acting like you don't know me. I'm assuming there's a reason.
The Doctor: Well, a fairly good one, actually.
Professor River Song: OK, shall we do diaries then? Where are we this time? Ah, going by your face, I'd say it's early days for you, yeah? So, um - crash of the Byzantium. Have we done that yet? Obviously ringing no bells. Right, um - oh, picnic at Asgard. Have we done Asgard yet? Obviously not. Blimey, very early days, then. Hoo! Life with a time traveler - never knew it could be *such* hard work. Um... [whispering] Look at you. You're *young*.
The Doctor: I'm really not, you know.
Professor River Song: No, but you *are*. [reaches to The Doctor's face and strokes his hair] Your eyes. You're younger than I've ever seen you.
The Doctor: You've... seen me before then?
Professor River Song: [hand moves to his shoulder, concerned] Doctor. Please tell me you know who I am.
The Doctor: [looks at her hand, then back to her face] Who are you?
Ahhh!!!! This was so heart breaking when I watched it! =(