Somkiat Chantra (25) will become the first Thai rider to race full-time in MotoGP next season with Honda-LCR, the team announced on Thursday.
Somkiat will replace Japan's Takaaki Nakagami, who will become a test rider, at the Honda satellite team.
"Stepping into MotoGP has always been my dream, and I will finally make it true," Somkiat said in a statement.
"I'm committed to learning, giving my maximum, and enjoying this new adventure. It will be difficult, but I will give my best."
Somkiat has won two races in Moto2 since making his debut in the class in 2019 and finished sixth in the riders' standings last season.
He is 10th in the championship this year with 64 points from 11 races.