In Doctor Who series 8 episode 6 The Caretaker, Clara has a friend named Adrian. When the Doctor looks at him, he looks like he recognizes him. Later, there are these conversations
DOCTOR: Go and canoodle with your boyfriend. Come on. I wasn't born yesterday. Far from it.
CLARA: You did recognise him.
DOCTOR: Possibly reminded me of a certain dashing young time traveller.
CLARA: Oh, of course you recognised him. I. Sorry. Stupid. I, I underestimated you.
DOCTOR: What about the handsome one, the one with the bow tie?
CLARA: Who? Adrian? No, no, no. He's just a friend and not my type.
DANNY: So, there's an alien, that used to look like Adrian. Then he turned into a Scottish caretaker.
Does Adrian look like a past incarnation of the Doctor?
Which doctor does Adrian resemble ?