Jerez de la Frontera, Spain - French rider Johann Zarco, 2017 MotoGP Rookie of the Year, has signed a two-year deal to join the Red Bull-backed KTM factory team from 2019.
KTM also confirmed Spanish rider Pol Espargaro would stay, leaving Britain's Bradley Smith without a ride.
Zarco is a double Moto2 champion and has been a consistent frontrunner with the non-factory Tech3 Yamaha team since he stepped up.
KTM made its MotoGP debut in 2017 and is an also-ran in a top category where Italian brand Ducati provides the main challenge to major Japanese manufacturers Honda, Yamaha and Suzuki.
KTM motorsports director Pit Beirer said at the Spanish Grand Prix on Thursday: "We had to trust in our capability to build a winning bike and Johann would not come over if he did not see and feel that trust.