Jack and The Doctor in “Last of the Time Lords”

[worried] But I keep wondering...what about aging? 'Cause, I can't die, but I keep getting older...The odd little grey hair, you know? What happens if I live for a million years?

[amused] I really don't know.

[laughs] Okay, vanity, sorry. Yeah, can't help it. Used to be a poster boy when I was a kid, living on the Boeshane Peninsula. Tiny little place. I was the first one ever to be signed up for the Time Agency. They were so proud of me...The Face of Boe, they called me. [The Doctor and Martha look at him in shock]