Britain's Alex Lynn has joined Williams as this season's development driver.
The 21-year-old, who won the GP3 feeder series in 2014, will mainly work in the team's simulator but will also drive at a test in Barcelona in May.
Lynn joins Valtteri Bottas, Felipe Massa and test driver Susie Wolff.
"We're always on the lookout for emerging home-grown talent, said deputy team principal Claire Williams. "Alex's impressive performances in GP3 caught the eye."
Lynn, from Essex, will dovetail his Williams role with a full season in the GP2 category in 2015.
He said: "I hope that with a strong year in GP2, while also helping to develop the F1 car throughout this season, I can follow in the footsteps of Valtteri Bottas, who joined the Williams team in exactly the same development driver role.
"Through hard work and determination, he has gone from winning the GP3 title to earning his place as a Williams F1 race driver."