"Ohhhh - I'm sorry, I haven't met anyone called that," the Doctor said regretfully, then added cheerfully, "But, you know, in this place, you never know who you'll meet next! If I meet him, I'll tell him I've seen you. Not that it'll be much help, really, 'cos you'll forget this place completely when you leave it. But I'm sure it'd be nice to see a familiar face."
He wouldn't mind seeing one himself, to be perfectly truthful.