Russian Nikita Mazepin will make his Formula 1 debut for Haas next season.
Mazepin, 21, third in Formula 2 with two races remaining, has signed a "multi-year deal", the team says.
Haas have not named their other driver, but Mick Schumacher, son of seven-time F1 champion Michael, is the favourite.
Team principal Gunther Steiner said: "Nikita has underlined his credentials in F2 this year, with two victories and a handful of podiums in a strong season."
Current drivers Romain Grosjean - who survived Sunday's huge crash during the Bahrain Grand Prix - and Kevin Magnussen are leaving the team at the end of the current season.
Mazepin said: "Becoming a Formula 1 driver is a lifelong dream come true for me. I really appreciate the trust being put in me by [team owner] Gene Haas, Gunther Steiner, and the whole of the team.
"I'm looking forward to starting our relationship together, both on and off the track, and I'm naturally keen to continue to demonstrate my abilities after a strong Formula 2 season."
Mazepin is the son of billionaire Russian industrialist Dmitry Mazepin, 52, who has bankrolled his career.
Nikita Mazepin was second in the GP3 feeder series in 2018, before finishing 18th on his debut in F2 in 2019.
He was third in the Asian F3 championship over the winter of 2019-20 before continuing in F2 this season, switching from the ART to Hitech teams.
He won so-called 'feature races' - the longer of two events on each F2 weekend which starts from a standard grid - at Silverstone and Mugello.
The second F2 race of each weekend is shorter and the grid is set by the finishing positions of the feature race, but with the top eight cars in reverse order.
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