He catches her with an arm around her shoulders and keeps them from knocking heads, but when she looks over at him, he gives her a squeeze. She doesn't look quite as excited as he does.
"Sorry, but, well, it's not exactly the first time-- but the Doctor doesn't remember, been over a year, maybe chemistry wins out-- are you okay?"
Yeah, his first thought is just to enjoy and be excited (and watch over and over later), but at least one of his next thoughts is concern for Rose.