Hailey Bieber shows off her toned abs in crop top and low-waisted jeans paired with leather jacket

Kim Kardashian shows off tiny waist in crop top and sweats as she holds hands with son Saint

Hailey Bieber showcases her summer-ready abs in capri shorts... after a grueling workout in NYC

Lottie Moss shows off her taut midriff in a crop top and mini skirt in sultry mirror selfies