Two champions swapped cars when Lewis Hamilton handed over the keys to his F1 car to Tony Stewart and Hamilton climbed into Stewart's NASCAR racer.
The pair met up at Watkins Glen circuit in New York, USA for the test drive swap shop. A pouring wet track meant neither was tempted to push the others' company car, but Hamilton came away impressed, saying: "I never in a million years thought I'd have the opportunity to drive a NASCAR."
Hamilton entertained the crowds with burnouts in the NASCAR and his own Formula One machine, while Stewart returned the compliment.
Stewart, who has two NASCAR titles to his name and has previously raced in IndyCars, said: "That was truly the experience of a lifetime. I've also told my guys in the pit that it's probably going to make my crew chief a little more stressed now because I'm going to want my NASCAR to handle like the F1 car all the time."