Nico Rosberg and Kazuki Nakajima have been retained by Williams for the 2009 Formula One season.

Williams test driver Kazuki Nakajima will make his grand prix debut for the team in Brazil later this month after being named as the replacement for Alex Wurz, who retired on Monday.

Williams have confirmed 21-year-old Japanese driver Kazuki Nakajima is to join the team as a test driver.