Alonso's shock move to Aston Martin left Alpine with an unexpected spare seat, which the team announced on Tuesday evening will be filled by Piastri. 

The Australian driver did not initially comment on the announcement, but later reacted on social media: "I understand that, without my agreement, Alpine F1 have put out a press release late this afternoon that I am driving for them next year.

"This is wrong and I have not signed a contract with Alpine for 2023. I will not be driving for Alpine next year."

The situation has moved incredibly quickly since Sebastian Vettel announced he would be retiring from F1 at the end of the season prior to last weekend's Hungarian Grand Prix.

Alpine had been confident of tying Alonso down to a new contract for 2023, while Piastri had been linked with the likes of McLaren and Williams.

Alpine team principal Otmar Szafnauer claimed that he had the first option on Piastri.

The 21-year-old Australian, who has been part of Alpine's junior programme for four years, has acted as the team's reserve driver for this season after missing out on an F1 seat after winning last year's F2 championship.

Esteban Ocon is Alpine's other driver.

Speaking about Piastri, who also won the F3 title in 2020, Szafnauer previously said: “Oscar is a bright and rare talent. We are proud to have nurtured and supported him through the difficult pathways of the junior formulae. 

"Through our collaboration over the past four years, we have seen him develop and mature into a driver who is more than capable of taking the step up to Formula 1.

"As our reserve driver he has been exposed to the team at the track, factory and testing where he has shown the maturity, promise and speed to ensure his promotion to our second seat alongside Esteban.

"Together, we believe the duo will give us the continuity we need to achieve our long-term goal of challenging for wins and championships.”