American teenager Santino Ferrucci is to drive for Haas at the two-day Silverstone test that follows the British GP.
Teams are obliged to run rookies on two of the four in-season test days, and with Esteban Gutierrez and Romain Grosjean having both run in Barcelona in May, Haas has to give both days next week to a youngster.
The 18-year-old from Connecticut is currently competing in the GP3 Series.
"Becoming a Formula One driver is my ultimate goal and I can't thank the Haas F1 team enough for this opportunity," said Ferrucci. "Nothing beats seat time, and the experience of driving a Formula One car and working with Haas F1 team will be invaluable."
"We brought Santino on with Haas F1 team because he's done a very good job of proving himself in each of the racing series he's competed in," said team boss Guenther Steiner. "We see Santino as a young American driver with a lot of potential who has earned this opportunity."
Also confirmed for the test is 17-year-old Russian Nikita Mazepin, who will do two days for Force India.