The 41-year-old two-time world champion has announced a move to Aston Martin on a multi-year deal from next season.
It means Piastri is likely set to join Esteban Ocon as Alpine’s drivers for the 2023 world championship.
Piastri, 21, won F3 in 2020 and F2 in 2021. He is currently the reserve driver at Alpine.
The rising star, managed by Australian racing icon Mark Webber, was this year controversially beaten to a Formula 1 seat at Alpha Romeo by China’s Zhou Guanyu.
That was despite the fact Piastri had defeated Zhou by a comfortable margin in the 2021 F2 championship.
While Piastri is yet to make his Formula 1 debut, the Victorian has had several Formula 1 test drives.
Alonso will join Lance Stroll at Aston Martin for the 2023 world championship.
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