To prepare for her role as Jean Grey in X-Men, Sophie transformed her diet and exercise routine, which she told Self in 2016 wasn't a regular routine to begin with. Working with celebrity trainer James Farmer, her fitness schedule consisted of workouts like hill sprints, kettlebells, and boxing, and she followed a "low-carb, Paleo-style" eating plan. Sophie worked out for at least an hour six times per week at the time, and she recently told Vogue that she still likes to box.