In the The Husbands of River Song The Doctor goes to the ship and asked the female
DOCTOR: Do I know you?
RIVER: You most certainly do not.
then he realizes its River but they say
RIVER: Don't use my name. Ever. How do you know me?
then he says
DOCTOR: Well, it's a tiny bit complicated. People usually need a flowchart
then he tries to get her to reconize him
DOCTOR: No, wait. That's your husband? RIVER: My husband, your patient. King Hydroflax. DOCTOR: Yes, that's who you're married to? Not anybody else? HYDROFLAX: My love, attend me, woman! RIVER: I fly to you. Is there a problem? DOCTOR: Right. So you don't recognise me, then? RIVER: Why would I recognise you? Later DOCTOR: Oh, no reason. DOCTOR: I'll be the judge of that. I'm the Doctor. RIVER: You know who you remind me of? DOCTOR: Yes, probably a chap with a big RIVER: My second wife. Then again DOCTOR: You know, don't you? RIVER: Know what? DOCTOR: Stop pretending. You know who I am. RIVER: Who are you? DOCTOR: You know who I am. It's, it's, it's me. RIVER: Great. Who are you?
Then later at the diner she says
RIVER: When you love the Doctor, it's like loving the stars themselves. You don't expect a sunset to admire you back. And if I happen to find myself in danger, let me tell you, the Doctor is not stupid enough, or sentimental enough, and he is certainly not in love enough to find himself standing in it with me! then she recognizes him and he says DOCTOR: (sotto) Hello, sweetie.
Why didn't River recognize the 12th Doctor? when he said Yes, probably a chap with a big was he talking about the 11th doctor matt smith or 10th doctor david tennet?