Kaia Gerber flashes her washboard abs after sneaking in a workout with boyfriend Jacob Elordi

Kaia Gerber bares her back and flaunts her taut tummy for Celine SS/21 campaign

Kaia Gerber stays comfortable in a blue hoodie while heading to a Pilates class in West Hollywood

Kaia Gerber and boyfriend Jacob Elordi sing along to the radio in the car after workout session