Williams has signed Formula 3 Euro Series frontrunner Valtteri Bottas as its official test driver for the 2010 Formula 1 season.
The 20-year-old Finn, who is managed by former world champion Mika Hakkinen, steps into the role vacated by GP2 champion Nico Hulkenberg, who has been promoted to the Williams race team this year.
"This is a great way to start 2010," said Bottas. "I am very honoured to have been selected by a team as prestigious as AT&T Williams, one of the most significant names in the sport."
Bottas pledged to do his utmost to justify Williams's faith in him.
"This is an important step in my career but now the real work starts to get to the top," he said. "I am sure I will learn a lot with the team and I trust that together we will achieve great results for the years to come.
"This opportunity gives me even more positive energy to improve as a driver and achieve my future targets as my ultimate goal will be to become Formula 1 world champion one day.
"I take the opportunity to thank Sir Frank Williams and the senior management of the team and also to thanks my management and my sponsors for all their work and support so far."
Bottas finished third in his F3 Euro Series rookie season last year with top team ART, and is among the 2010 title favourites having completed a deal to stay with the squad.
Sir Frank Williams added: "Valtteri's CV is very impressive, with a long list of success in the right junior formulae. We hope that the role of official test driver in our squad will provide him with another step in his development. We wish him all the best in the Formula 3 Euro Series this season."