"Thank you! I thought so." Only the Doctor would take that bizarre conglomeration of words and consider them a compliment. But he looked faintly surprised at what she'd been told.

"He's me, actually. Me, but a few centuries earlier. When we die, my kind change personalities and appearance, but retain our core self and our memories."

He waves dismissively. "Chicken, egg, the chick has to happen somewhere en route, don't you think?"