Mick Schumacher will be reserve driver for McLaren during the 2023 season.
The German lost his race seat for this year when the Haas team dropped him for Nico Hulkenberg.
Mercedes signed Schumacher as reserve driver in December and they have agreed that he can also be used by McLaren, who are powered by the Silver Arrows.
The 23-year-old, son of seven-time world champion Michael, will deputise for Lando Norris or Oscar Piastri if either are unavailable to race.
His best result in two seasons at Haas was sixth at the 2022 Austrian Grand Prix.
The new F1 season starts in Bahrain on 5 March.