I defy anyone to watch this video of Lanvin models Karen Elson and Raquel Zimmerman dancing to Pitbull's deathless clerb hit "I Know You Want Me (Calle Ocho)" without cracking a smile. I've watched it four times this morning, each time asking myself what is it exactly that's so funny? Something about the self-consciousness of the moves, maybe, the strangely ungainly proportions of beheeled runway models in motion, or Raquel's little smirks to herself. Perhaps it's just the sudden appearance of Alber Elbaz himself. He looks like he's having a really good time.