Nico Rosberg has confirmed he will leave Williams following this season's final race of the Formula One season in Abu Dhabi on Sunday.
Speculation has been rife for the last two months that Rosberg was to end his four-year association with the Grove-based team.
Although the 24-year-old refused to divulge which team he will race with next year, it has been an open secret he will move to Brawn GP as new world champion Jenson Button's team-mate.
It is understood Rubens Barrichello will then switch to Williams on a one-year contract.
"This is my last race for Williams," revealed Rosberg.
"It's a bit strange because for four years it has been the only team I've worked with, so it's been a long time.
"I get on really well with everybody, a lot of respect has built up with all the mechanics, so it is going to be quite strange to leave.
"I can only use the opportunity to really thank the team because it has been very good for my career.
"Sir Frank, Adam Parr, Sam Michael and Patrick Head have really supported my career all these years, so quite a big thank you to them."
Rosberg stopped short of naming Brawn as the team he will now sign for, adding: "I don't want to talk about my future.
"I just want to say I won't be with Williams because that's sure."