Mick Schumacher was dropped by Ferrari as a reserve driver on Thursday and immediately signed with their rivals Mercedes in the same role.
After Ferrari announced the 23-year-old German was leaving after four years in their academy by mutual agreement, Mercedes said they had signed him.
Mick's father Michael won five driver titles with Ferrari before finishing his career with three seasons at Mercedes.
Mick Schumacher raced the last two seasons for Haas, which uses Ferrari engines.
He failed to register a point in 2021. This year, his best finish in 22 races was sixth.
He ended up 16th in the driver standings. Haas dropped him in November and signed 35-year-old compatriot Nico Hulkenberg
Mercedes, who struggled to cope with changes to Formula One's technical rules last season, are busy developing their 'W14' model.
"Mick will play an important role in the ongoing development of the W14. He will conduct regular work in the simulator," the team said on their web site.
Mercedes has seven-time world champion Lewis Hamilton and George Russell, who finished fourth in the standings last season, as their race drivers.