Ilott had his first experience in a Formula One car during the 2019 in-season test at the Circuit de Barcelona-Catalunya, driving the Alfa Romeo Racing C38. He completed 41 laps before his running was cut short after a crash at turn 3. Ilott was due to make his Formula One weekend debut during the first practice session (FP1) of the 2020 Eifel Grand Prix, driving for the Ferrari-powered Haas F1 Team, but the Friday practice sessions were cancelled because of poor weather.