Sergey Sirotkin has returned to Renault's Formula 1 line-up by becoming the team's official third and reserve driver for the 2019 season. 

The Russian, who was left without a full-time F1 seat for 2019 after Williams opted to field Robert Kubica and Formula 2 champion George Russell, has returned to the team he carried out the same role for back in 2017. 

Sirotkin will dovetial his F1 commitments with a programme in the FIA World Endurance Championship with SMP Racing throughout 2019. 

The 23-year-old picked up a single point and finished 20th in the drivers' standings during his rookie F1 campaign in 2018 as Williams endured a torrid season. 

Renault has also confirmed that young driver Jack Aitken will be retained at the French squad to carry out a test role, with new Renault Sport Academy member and F2 driver Guanyu Zhou taking on a development position. 

“I am very pleased to rejoin my friends at Renault F1 Team and return to Formula 1," Sirotkin said. 

"We are well acquainted with the team, I spent the whole of 2017 in their factory and in the garage.

"It will be interesting to learn how far Renault has advanced in the development of the car over the past year; last season we were rivals and I could not see the work from the inside.

"I am pleased to join the team as Third & Reserve Driver and work alongside Nico Hülkenberg and Daniel Ricciardo.”

Renault team boss Cyril Abiteboul added: "We’re very happy to reveal our full 2019 driver line-up. It’s a very strong and experienced team of drivers.

"Nico and Daniel are an exciting combination and will be strongly supported by Sergey, Jack and Guanyu.

"In Sergey’s return, we have a driver who has experienced a full season racing in Formula 1 and that knowledge will be beneficial to developing our package.

"Jack has also impressed us when testing our Formula 1 machinery, while Guanyu will complement the experienced team. All of them have an important role to play this season and we look forward seeing them all in action.”