Gov Kodos wrote:
He could whisper it to River, who'll look amazed and awed, but the audience won't hear it and nest the Doctor will swear her to tell no one his name. She will say yes, which must be the truth, and we get to keep on wondering 'Doctor Who'. Or some variation there of, so the mystery remains. Whatever, I doubt we'll learn his name.
Which would also fit with her future self whispering it to him when they first meet...