Rubens Barrichello will almost certainly drive for Williams next season.

Ahead of Sunday's Brazilian Grand Prix, which Barrichello effectively must win to keep his title hopes alive, the 37-year-old said: "It is true I am talking with Williams and Brawn."

It would appear he is wasting his time with Brawn, who are understood to be close to pairing Jenson Button with Williams' team-leader Nico Rosberg in 2010. That line-up has been encouraged by Brawn's engine suppliers Mercedes-Benz, who are keen to have a German driver with the British-based outfit.

But it a risky strategy because Barrichello still has an outside chance of pipping Button to the drivers' crown and so take the coveted No1 with him to Williams.

The Brazilian knows he carries the weight of expectation from the passionate fans at Interlagos. And although he is trailing Button by 14 points with a maximum of 20 to be won this season, Barrichello believes he is up to the task. "I will be giving it my all to achieve the best possible result," he said. "The Brazilian Grand Prix is always special for me and I am very proud of my home race. It's fantastic to race in front of the Brazilian fans and receive so much support."

Button, who can put the title beyond the reach of Barrichello and Red Bull's Sebastian Vettel by finishing at least third, admitted: "This is an important race for me. It's going to be a challenge, but one that we are all looking forward to."