This story was originally published on January 4, 2017.The Hadids have recently discovered the ease and comfort tracksuits . They're probably too young to remember the original matching set in all its early-aughts glory, but no matter: Track is back . Whether or not it's the first time they're experiencing this no-fuss, no-thought outfit, hey, at least the ultra-comfortable look is cool again. Each athleisure-embracing starlet has her own take on the classic: Margot Robbie and Cara Delevingne like to twin , Gigi Hadid likes hers personalized . Younger sister Bella has embraced this comeback trend in her off-duty style — and she's already landed on an outfit formula that works for her.