Everybody, it's time to set your alarms! In less than 24 hours, Isabel Marant for H&M will hit stores — and if you're still deciding on those select pieces to purchase, why not take your cue from these stylish celebrities? Right now, just across the pond, Sienna Miller is cozied up in an oversize cardigan, and last night, Milla Jovovich donned the covetable collaboration to celebrate its launch in New York. These style setters are not alone. We've rounded up Hollywood's hottest to don Isabel Marant — including, of course, the ever-buzzed-about H&M collaboration — here, in the gallery.