Sergey Sirotkin is to remain with Renault as reserve driver, his third season with the French team.
The Russian, who made 21 starts for Williams, scoring his best result at Monza where he finished tenth, will join Renault ahead of this weekend's Austrian Grand Prix and will be present at all the remaining F1 races.
"It's great to be back with Renault as reserve driver," said Sirotkin. "I know the team very well having been with them throughout the 2019 season.
"I understand the importance for a team to have a driver ready to fill in quickly should the opportunity arise, especially given the current situation the world is in. I've been keeping sharp and focused and I would be well prepared to race a Formula 1 car again. I'm looking forward to seeing my friends at Renault soon."
"We're pleased to welcome Sergey back to the team for this year," added Cyril Abiteboul. "Given the current circumstances we find ourselves in, we must have plans in place for any situation which might occur. We know Sergey very well and he, likewise, knows the team. We're looking forward to welcoming Sergey this weekend in Austria."