George Russell will leave his role as reserve driver for Mercedes to take up a full-time seat with Williams in Formula One next season.

The British-based team said Friday it signed a "multi-year agreement" with the 20-year-old Briton.

Russell leads the Formula 2 championship standings and is the test and back-up driver at world champion Mercedes.

He says racing in F1 "has been a life-long dream" and that "it feels surreal that I will now be lining up on the grid, alongside drivers whom I have admired for years."

Williams deputy team principal Claire Williams says Russell "is already highly regarded in the paddock and a driver whose career we have been watching for a while."