Fernando Alonso has admitted to joining Ferrari from the Enstone-based Renault team a year earlier than initially agreed.

Alonso has signed a three-year deal from next season reputed to be worth £55m.

That’s still £20m shy of the pay Kimi Raikkonen – who he replaces – is understood to have earned with the team over the last three years.

However, the double world champion now has the chance to add to the titles he won with Renault in 2005 and 2006.

After initially signing with Ferrari this summer to start in 2011, Alonso will leave Renault, who he rejoined in 2008 after a spell with McLaren, at the end of this year.

“I'm very happy and very proud to become a Ferrari driver,” said Alonso. “Driving a single-seater from the Prancing Horse is everybody's dream in this sport, and now I have the opportunity to make this dream come true.

“We had an agreement this summer, starting in 2011, but then over the last few days the picture changed.”

As part of the cascade of driver moves that will follow Alonso's switch, BMW Sauber's Robert Kubica is understood to have already signed a contract to replace him at Renault.