Allan McNish admits the transition from Formula One back to sports cars could prove tricky, acknowledging that he faces a crucial test this week.
McNish has been in Formula One for three years
McNish has joined the Team Veloqx-run Audi UK squad for whom he will race in the Le Mans 24 Hour and the inaugural four-race Le Mans Endurance Series.
This week he is at Road Atlanta for his first test of the new car.
"This test is critical for me because it's been a few years since I've driven the Audi R8," he said.
"The Audi and F1 cars are different and I've got to get that feeling back.
"I've got to get the understanding of even silly things, like this Audi has got
slick tires, I've been used to grooved tires.
"From my point of view, it's important to test, but from the team and that
gelling aspect of it, it's critical."
McNish won the 2000 American Le Mans Series title during his first spell in sports cars.
"I loved my time in the American Le Mans Series and I'm glad to be back," he added.