Spain's 250cc double world champion Jorge Lorenzo has been confirmed as Valentino Rossi's MotoGP team-mate at Yamaha next season.
Lorenzo has earned his chance in MotoGP
Lorenzo, 20, who won this year's 250cc title for Aprilia, finished seventh in Sunday's season-ending Valencia GP.
Yamaha have also said that five-times MotoGP champion Rossi would change tyre manufacturer to run on Bridgestones in 2008. Lorenzo will use Michelins.
Rossi had problems with the Michelins on his bike for much of this season.
Yamaha said that in order to ensure confidentiality for each tyre company, the two riders would have separate pit boxes and managers.
Rossi, 28, came third in this year's championship behind Casey Stoner and Dani Pedrosa.
He was forced to drop out of the Valencia race on Sunday with a technical problem after deciding to ride with a broken hand sustained in a qualifying
It was the first time the Italian has finished outside the top two in any category since he was ninth in his rookie season in the 125cc class in 1996.