Williams will announce its 2017 driver pairing on November 3 (next Thursday), with Canadian F3 driver Lance Stroll expected to join Valtteri Bottas at the team.
The announcement will close off another two places on next year's grid, with Stroll becoming the first rookie to be confirmed for 2017.
Stroll, Williams' current development driver, has been strongly linked to the team since Felipe Massa announced his retirement at the Italian Grand Prix, but title sponsor Martini wanted to wait for him to turn 18 years old before making an announcement. Stroll comes to the team off the back of title success in F3 this season and has completed a series of tests in a two-year-old Williams to prepare himself for the step up to F1.
Bottas will be retained after Williams decided to take up its option on his services for 2017. The Finn had been linked to a Renault drive, but by remaining at Williams will rack up his fifth consecutive season at the same team.
The announcement will take place at the team's headquarters in Grove, UK.