Supercross frontrunner James Stewart has signed a multi-year contract to participate in both Joe Gibbs Racing's motocross and NASCAR teams.

Joe Gibbs Racing announced also that it had extended its relationship with Yamaha Motor Corporation, U.S.A. racing exclusively Yamaha motorcycles through 2014.

Meanwhile, Stewart will get a chance to sample stock car racing, the team planning to try running him at NASCAR regional levels next year before possibly attempting a Nationwide Series outing.

"I am excited about joining the Gibbs racing family," said Stewart, the first afro-american rider to win a Supercross title.

"I have also had an interest in car racing and we are going to explore my potential in that sport through the NASCAR side of the operation."

Stewart is expected to test a stock car within the next month as he attempts to gradually transition into what could be his next move once his days on two wheels are over.