Alonso had expected 2011 Ferrari move

It had long been thought that Alonso was destined to eventually join Ferrari, but when the Italian team extended Felipe Massa and Kimi Raikkonen's contracts through 2010, it appeared that 2011 would be the soonest he could arrive - and Alonso confirmed that this was the initial plan.

But Ferrari recently began negotiating to end Raikkonen's deal a year early to make room for Alonso, and today the team announced that the Spaniard would join its line-up for three years from 2010.

"We already had an agreement this summer starting in 2011, but then, [in] the last days, the picture changed and we decided to anticipate my arrival in Maranello by one year," said Alonso.

Team boss Stefano Domenicali confirmed that Alonso's arrival had been brought forward.

"With Fernando we started talking about a prospective [drive] for 2011, but then there were the conditions to anticipate the start of our relationship already as of the upcoming championship," he said. "We preferred to take the opportunity."

Alonso added that he was achieving a long-held ambition by joining the legendary team.

"I'm very happy and very proud to become a Ferrari driver," he said.

"Driving a single-seater from the Prancing Horse is everybody's dream in this sport and today I have the opportunity to make this dream come true. Above all I want to thank Ferrari chairman Luca di Montezemolo, who really wanted this three-year contract.

"I'm sure that, together with Felipe, we'll offer Ferrari and the fans from all over the world some great satisfaction. I can't wait to start working with my new team."

He also paid tribute to Renault, which took him to the 2005 and 2006 world championships, and where he returned in 2008 after his unhappy year at McLaren.

"The years at Renault were fantastic," said Alonso. "I wish the team all the best and let's hope we gain some good results in the last races this year."