I know it may be
but here is a little info.
The damn MOTO GP website wont let me copy and paste, so here is the link.
Following the conclusion of the 2007 season, Yamaha Motor Co., Ltd and Yamaha Motor Racing Srl are pleased to be able to confirm the final line-up of their 2008 Factory Team.
Seven-time World Champion Valentino Rossi and two-time 250cc World Champion Jorge Lorenzo will contest the 2008 MotoGP World Championship as team-mates in the Fiat Yamaha Team.
Yamaha can also confirm its plan to run Valentino Rossi on Bridgestone tyres in 2008, while Jorge Lorenzo will be racing with Michelin tyres.
In order to facilitate the use of both Michelin tyres and Bridgestone tyres within the Yamaha Factory Team and to ensure confidentiality of data for each tyre company, Yamaha will organize separate rider pit boxes, but the Fiat Yamaha Team will continue to operate and race as one team.