Natalie Portman's 15 or so appearances on David Letterman through the decades -- from ages 13 to 29 -- have yielded two things: 1) Dave really, really loves her; and 2) no one can remember for the life of them what age Portman was when she first appeared on the show. (Answer: She was 13, and she was plugging her breakout role in Luc Besson's "The Professional," but not without a little bit of sass).
A running inside joke, or a case of collective memory loss? (We're guessing it's the former.) Or has Portman merely been entertaining Dave all along, bless his old soul? Watch HuffPost Celebrity's video mashup of Portman on the show, and you be the judge.
Natalie Portman's all grown up! Check out photos of the actress over the years: