Takaaki Nakagami will remain with the LCR Honda MotoGP team for the 2019 season.
Nakagami graduated from Moto2 to join an expanded two-bike LCR line-up in the premier class this year, racing a year-old Honda RC213V in the colours of long-time sponsor Idemitsu.
With four races to go, he lies 20th in the points standings with a best finish of 12th, and sits third in the battle for rookie of the year honours behind Tech3 Yamaha's Hafizh Syahrin and Marc VDS Honda rider Franco Morbidelli.
It had long been expected Nakagami would continue at Lucio Cecchinello's team for a second season, and the news was finally confirmed a few days ahead of his home grand prix in Japan.
"First of all I am really happy to continue with LCR Honda Idemitsu Team in 2019," said Nakagami.
"A big thank you goes to our sponsor Idemitsu for its great support and of course to Honda HRC for believing in my skills and providing a competitive technical package.
"This team is very professional and I could not ask for more in my debut season in the premier class, so I am very happy to continue with Lucio and his crew.
"I can't wait to start the new season but at the same time I am very focused on my home race in Motegi and the last races of this 2018 championship."
LCR boss Cecchinello said working with Nakagami had been "a real pleasure" so far so he was pleased Honda and the rider's sponsors were willing to continue into 2019.
"Debuting in the MotoGP class is not an easy transition for a rider because the level is extremely high but Taka has demonstrated very remarkable skills and a will to learn, finishing quite often as the best rookie of the category," he added.
The announcement leaves just one place on the 2019 MotoGP grid to be officially filled at Avintia Ducati, which is poised to retain the currently-injured Tito Rabat for a second season.
2019 MotoGP line-up so far
Honda: Marc Marquez, Jorge Lorenzo
Ducati: Andrea Dovizioso, Danilo Petrucci
Yamaha: Valentino Rossi, Maverick Vinales
Suzuki: Alex Rins, Joan Mir
Aprilia: Aleix Espargaro, Andrea Iannone
KTM: Johann Zarco, Pol Espargaro
Pramac Ducati: Jack Miller, Francesco Bagnaia
Tech3 KTM: Hafizh Syahrin, Miguel Oliveira
LCR Honda: Cal Crutchlow, Takaaki Nakagami
Avintia Ducati: Karel Abraham, TBC
SIC Yamaha: Franco Morbidelli, Fabio Quartararo