Toro Rosso has confirmed that Brendon Hartley will make his Formula 1 debut with the team at the United States Grand Prix, alongside Daniil Kvyat.
Hartley, a former member of the Red Bull junior scheme, has been drafted in to replace Pierre Gasly, who will contest the clashing Super Formula finale at Suzuka.
It will mark a race-by-race overhaul of Toro Rosso's line-up, after the outfit fielded Gasly and Renault-bound Carlos Sainz Jr. at the last event in Japan.
Hartley, 27, claimed the World Endurance Championship title in 2015 and currently leads this year's standings, having taken victory at the Le Mans 24 Hours.
"What an amazing feeling," said Hartley. "This opportunity came as somewhat of a surprise, but I never did give up on my ambition and childhood dream to reach F1.
"I have grown and learnt so much since the days when I was the Red Bull and Toro Rosso reserve driver, and the tough years I went through made me stronger and even more determined.
"I want to say a huge thanks to Red Bull for making this a reality, and to Porsche for allowing me to do this alongside the World Endurance Championship.
"COTA is a track I really enjoy and one I have raced at recently. I'm trying not to put too many expectations on my F1 debut, but I feel ready for it."
