River most certainly isn't the Doctor. She's got far too many shapely curves to pass for the Doctor. She might even have been offended if he ever thought she happened to be the Doctor at all!

Now this man, he made her skin positively tingle. Like an electric current had passed through her body. It was that same electric heat that she felt whenever she came face-to-face with the Doctor.

"That? Oh, the TARDIS? Just taking her for a bit of a joy ride. Thought I'd see a bit of the universe. I do hate being stuck in one time stream."