The singer-and-model - who has a six-year-old daughter, Scarlett, with the White Stripes frontman - is huge admirer of her former spouse's fashion sense and says he helped her with her own style.
She said: ''He's one of the most stylish men I've ever met. He doesn't follow fashion, but he's very creative. He's got a really unique take. It's not based on what's hip or what's cool or what the flock is following. It's very specific to him. Just by watching him, he's helped me define my own sense of style.''
As well as admiring Jack's look, Karen is also a fan of how Helena Bonham Carter dresses.
She told Vogue magazine: ''I love her style - she's so playful, ridiculously playful. I also feel that, if she does follow fashion, it's from gut instinct, which is exactly how I follow fashion.