Nyck de Vries will replace Alex Albon at Williams for the Italian Grand Prix after the Thai driver contracted appendicitis.
The Dutchman, who won Formula 2 in 2019 and Formula E in 2021, is in the running to be Alex Albon's teammate next year as there is ongoing uncertainty about the future of Nicholas Latifi.
He now has a golden opportunity to underline his credentials for that role in what will be his F1 race debut.
De Vries will take part in third practice on Saturday, which is followed by qualifying in the afternoon
Williams are believed to be weighing up De Vries and American Formula 2 driver Logan Sargeant for the 2023 seat.
De Vries has had plenty of F1 experience this year and took part in first practice for Aston Martin at Monza on Friday, having done the same for Williams at the Spanish Grand Prix and for Mercedes at the French Grand Prix.
Albon is undergoing treatment for appendicitis having fallen unwell on Saturday morning.