If you’re watching “The Undoing,” on HBO on Sunday nights, you might have been struck in the second episode by this green velvet (I think it’s velvet?) coat worn by Nicole Kidman. While this isn’t the greatest photograph of it — you don’t get a good sense of the shape, which is a dramatic, retro-looking nipped waist and long flared skirt — look how the coat, framed by her mane of red hair, draws all eyes to her in this scene of men in dark suits in a room with pale walls. Elsewhere in the episode, we saw overhead shots of her on a Manhattan street, the coat swirling around her as if she were some sort of sorcerer. Kidman’s character, Grace, is a woman of some mystery; this highly covetable coat adds to that spell. I don’t know what’s coming next on this show, but I do hope we see this coat again. It’s playing its part well.