The 20 year old was a test driver for Williams and recently won the GP2 Championship.
Nico made his Formula One debut with WilliamsF1 at the age of 17 in a one-off test in 2002 making him the youngest driver in history to pilot a Formula One car.
Nico Rosberg is the son of Keke Rosberg who won the 1982 Formula 1 World Championship with Williams running a Ford Cosworth!
Team Principal Frank Williams said:
Nico Rosberg said:I believe I am one of many in Formula One who is genuinely excited about the prospect of Nico Rosberg. Given the attention he commands, I am delighted he has signed with us for next season.
Nico will be testing for the team at the end of November at Barcelona making the debut run of the V8 Cosworth.For quite a few years, I kept a number of options open, such as continuing my education, but this announcement is the validation after ten years of racing that I have chosen the right direction. Winning the GP2 title this season, especially given the competition, was a satisfying achievement, but of course this development is the crowning glory of a great year. I am really looking forward to starting work at the end of this month and learning as much from the team as I possibly can.
The seat at Williams became available after Williams and Button reached a deal allowing Button to stay at BAR.
Nico Rosberg will partner Australian Mark Webber
Full Williams Statement