a) Play it cool and casually ignore her as you secretly kick yourself for not wearing your best outfit ever.
b) Strike up conversation; ask if she's enjoying her time in the city, what she's thought of the shows so far, etc.
If you're a Hollywood actor and the boyfriend of Kirsten Dunst, the answer will always be the latter.
Yesterday, Garrett Hedlund and Dunst were spotted chatting with Wintour on the Saint Laurent FRow. Well, Garrett was chatting. Kirsten was definitely doing the playing it cool, staying silent thing.
Wintour or no Wintour, Garrett and Kirsten also happen to be the cutest (and best dressed) couple of the fashion week FRow so far. Move over, Kim and Kanye!
See more of the actress below: