I just read on Twitter that this is vintage YSL from Decades, the truly amazing vintage store here in Los Angeles. (I have this personal rule that if there is a parking spot open in front of Decades/DecadesTwo [DecadesTwo is the consignment arm of the store], I am required to go inside and poke around, all of which is why I own these amazing INSANE Miu Miu t-strap shoes that have both glitter AND snakeskin on them and I am a better person for it/them.)
I love it, and — more importantly — I love it ON HER. If I see her at Decades, I will tell her so. (Not really. I’ll actually just tweet that I am staring at Jessica Chastain through a rack of trench coats, and then I will scamper away. But I will think it, really hard.)