Valtteri Bottas was in action at the Circuit Paul Ricard on Friday, as part of a tyre test session for Pirelli.
Bottas' Mercedes team mate Lewis Hamilton had turned out the day before, and completed 114 laps for Formula 1's tyre supplier.
After completing his day behind the wheel, Hamilton handed over the W08 to Bottas for the second day of testing. The Finn put in 109 laps in warm and sunny conditions at the circuit. That made a total of 223 laps completed by Mercedes over the two days.
Hamilton earlier said that he had volunteered to participate in this week's test. That's unusual for the Briton, who is known to hate carrying out in-season testing.
However the test did give Hamilton a chance to get to know the 5.861km (3.642-mile) circuit, formerly owned by former F1 supremo Bernie Ecclestone. It will be the venue for next year's return of the French Grand Prix to the F1 calendar.
On-track testing time is currently strictly limited for teams in Formula 1. However, Pirelli have been allowed 25 days of tyre testing over the course of the season to help develop 2018 compounds.
Bottas previously took part in a one-day test for Pirelli at the Hungaroring last month. It was held alongside an all-team in-season test, with rising GP3 star George Russell the official Mercedes representative for the occasion.
In 2016 Pirelli's test were obliged to use modified cars from the previous season. Only Mercedes, Red Bull and Ferrari had the resources to prepare the 'mule' car required
But with the big technical changes introduced this season, current tests need to use their 2017 chassis for the sessions to be relevant. As a result, all 10 current F1 teams are involved in Pirelli's programme this year.
In order to ensure that drivers don't gain any advantage over their rivals, the testing is carried out 'blind'. That means the driver and the team taking part are unaware of the compound being tested. All data gained from the tests is shared equally among the teams.
Pirelli's next tyre test is scheduled to take place following the Mexican Grand Prix at the end of October. Sauber will work with the French tyre provider for two days. Force India is also scheduled to participate for one day at the Autódromo Hermanos Rodríguez.
The final test is due to be held mid-November following the Brazilian Grand Prix. It will be McLaren's turn to take part, with the MCL32 scheduled to run for two days at Interlagos.
Pirelli, Lewis Hamilton, Valtteri Bottas