Barrichello celebrates victory at Monza
Brazilian veteran Rubens Barrichello and German rookie Nico Hulkenberg have been announced as Williams' new driver pairing for the 2010 Formula 1 season.
The duo come in for German driver Nico Rosberg, who is set to replace 37-year-old Barrichello at Brawn GP, and Japan's Kazuki Nakajima.
Hulkenberg, 22, was Williams' test and reserve driver this season.
Barrichello was third in this year's drivers' championship, with Brawn team-mate Jenson Button taking the title.
Barrichello was in contention for the championship until the penultimate race in Brazil and finished the season 18 points adrift of Button, and seven behind the runner-up, Red Bull's Sebastian Vettel.
Highlights - Barrichello masters Monza
He spent six years as Michael Schumacher's team-mate at Ferrari, finishing runner-up in the championship to the German in 2002 and 2004.
He had previously driven for the Jordan and Stewart teams, and left Ferrari to join Honda in 2006, being kept on when the team was turned into Brawn last winter.
Barrichello is renowned as an excellent test driver, and is one of the most popular characters in F1.
Team principal Frank Williams said: "He is not only the most experienced driver in Formula 1 but a passionate and talented driver who fought hard for the drivers' championship this year.
"Nico Hulkenberg won the GP2 Championship this season as a rookie and has previously won the F3 Euroseries, Formula Masters, A1 GP and Formula BMW Germany."
"Inside Williams we have a big spreadsheet which basically maps a driver's achievements from the age of eight and the reference in that spreadsheet has been Lewis Hamilton because of what he did from eight years old to get into F1," added Williams technical director Sam Michael.
"Basically Nico Hulkenberg has been on exactly the same path, coming up obviously through different countries.
"There's no point in putting a rookie in the car unless you think he can be a world champion."
Nakajima ended the season in Abu Dhabi on Sunday with the unfortunate distinction of completing all 17 races without scoring a point.
Barrichello entered F1 in 1993 - a year before his close friend and compatriot Ayrton Senna was killed after a crash in a Williams car at Imola - and will be the first race winner to drive for the team since Colombia's Juan Pablo Montoya and Germany's Ralf Schumacher in 2004.
Williams, who have not won anything since 2004, will be Barrichello's sixth team.
Highlights - Barrichello wins in Valencia
"I am very hopeful of having a very competitive car next year, so that is what I want from myself. I want to go on and keep on winning," Barrichello said.
Barrichello is Formula 1's most experienced driver, with a record 285 races to his name and 11 victories. He is now on course to become the first driver to have started 300 grands prix.
"Rubens was with our team for four years and we regard him as a highly experienced and talented driver whose contribution to the team over that period was significant," said Brawn GP boss Ross Brawn.
"This year was a very special season for Brawn GP and I'm extremely proud of the spirit in which our drivers fought for the championship.
"Rubens contributed hugely to our success in the constructors' championship with two great victories in Valencia and Monza, along with numerous podiums, and he was a pleasure to work with."
Williams announced over the weekend that they would be switching from Toyota to Cosworth engines next year.