Russian Sergey Sirotkin has been signed by Renault as a test driver and will take part in first practice at his home grand prix this weekend.
The 20-year-old, who races in the GP2 feeder series, will drive Kevin Magnussen's car at Sochi on Friday.
Renault said Sirotkin had joined on a "long-term development plan", but has given no details of any F1 outings.
The team already has an official third and reserve driver in Frenchman Esteban Ocon, who is on loan from Mercedes.
Renault racing director Frederic Vasseur described Sirotkin as "one of the most promising drivers from the junior categories".
Sirotkin said: "This is a great opportunity for me, although it has all come together so quickly. I still can't quite believe it.
"This is, however, the moment that all young racing drivers are working towards, and I am determined to learn as much as I can, as quickly as I can."
Sirotkin previously had a similar relationship with Sauber, who signed him in 2013 in a partnership with Russian investors with a view to him racing for the team the following year.
However, although he took part in first practice at the 2014 Russian Grand Prix, he split with the Swiss team soon afterwards.
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