George Russell will race for Mercedes next season in an all-British lineup with seven-time world champion Lewis Hamilton, the Formula One team said in a widely-expected announcement on Tuesday.
Russell, who is in his third season at Williams, will replace Finland's Valtteri Bottas, whose move to Alfa Romeo was made official on Monday.
The 23-year-old will be Hamilton's first new teammate since Bottas, now 32, also joined from Williams to take the place of retired 2016 world champion Nico Rosberg in 2017.
Russell has already raced once for Mercedes, a standout performance at last December's Sakhir Grand Prix in Bahrain when Hamilton tested positive for COVID-19 and was unable to start.
Russell qualified on the front row and led from the start but finished ninth after the team made a mess of the pitstop and he then suffered a late puncture after an impressive fight back through the field that also brought him the fastest lap.
He scored his first points for Williams this season, again catching the eye with a sensational qualifying performance in the wet in Belgium to put his uncompetitive car on the front row.
He took second place in that 'race' in Spa that ended after a couple of laps behind the safety car.
Mercedes team boss Toto Wolff said the decision to replace Bottas had nonetheless not been an easy process or a straightforward decision.
The Finn was strongly backed by Hamilton, who has had a relatively easy time over their years together and has won the last four titles, but Russell is managed by Mercedes and has long been seen as the face of the team's future.
Mercedes have won the last seven drivers' and constructors' championships and are leading the current team standings after 13 races, although Hamilton is three points behind Red Bull's Max Verstappen.
Hamilton, 36, has a contract for 2022 and 2023.