The moves comes just days after McLaren signed a lucrative sponsorship deal with Vodafone.

Team boss Ron Dennis said: “It’s great that our strong belief in the strength and competitiveness of the Vodafone McLaren Mercedes package has been further endorsed by the world champion.”

Alonso revealed he is excited by the prospect of a new challenge at McLaren after giving Renault their first world championship as a constructor last season.

Today’s news is likely to fuel talk of a potentialRenault withdrawal from Formula One in the near future but Alonso, who is managed by Renault boss Flavio Briatore, is looking forward to a new life with McLaren.

The Spaniard said: “To become part of a team with such a desire to succeed and passion for performance is a dream come true for any Formula One driver.

“I’m very excited about 2007 and the fantastic opportunity to drive for Vodafone McLaren Mercedes. It will be a new beginning for me and a tremendous challenge and from what I have heard about this exciting new partnership there is something to look forward to.

“Obviously I will be sad to leave Renault but sometimes possibilities come along which are just too good to miss.

“I’m pleased that we are able to make this announcement already now as it will allow my current team and I to focus 100% on defending the world championships next year.”

Dennis revealed he has yet to decide which of his current drivers will make way, although Raikkonen has been strongly linked with a move to Ferrari to replace Michael Schumacher in 2007.

He added: “We are in discussions with our current drivers, Kimi Raikkonen and Juan Pablo Montoya, regarding the 2007 season.

“Both Juan Pablo and Kimi are extremely talented, professional and competitive Formula One drivers and they have and will continue to concentrate on our joint challenge for the championships.

“Fernando and McLaren Mercedes wanted to make the announcement as soon as possible in a controlled and professional manner to allow McLaren Mercedes, Fernando, Kimi and Juan Pablo to focus on the preparations for the 2006 season.

“Our aim for next year remains absolutely clear to everybody within the team - we want to win races and be in a position where we might have two Formula One world champions driving for Vodafone McLaren Mercedes in 2007.”

Today’s news leaves Renault on the lookout for a new driver for 2007. Rising Finnish star Heikki Kovalainen, also managed by Briatore, is almost certain to step into Alonso’s shoes. He was already due to test for Renault prior to a planned race seat in 2007.