Canadian Formula 2 driver Nicholas Latifi will join Williams as a reserve driver in 2019.
Latifi joins the team from Force India, where he held the role of test and reserve driver this year. In his new role with Williams he will take part in six Friday practice sessions, one pre-season test and two in-season tests.
The 23-year-old scored one victory in F2 this year at the Spa-Francorchamps sprint race and finished the season ninth overall.
"I'm thrilled to be joining an iconic team like Williams as a Reserve Driver for 2019," he said. "It's a fantastic opportunity to continue my F1 development, and to build my on-track experience with more FP1 sessions and the rookie and Pirelli tests.