Fernando Alonso will make a surprise switch to McLaren in 2007 after deciding to turn his back on the Renault team that helped him capture the Formula One World Championship this year.
The deal comes just days after McLaren announced a major new sponsorship deal with mobile telephone network supplier Vodafone from the start of the 2007 campaign.
Alonso, who had been widely expected to remain with Renault after his contract expired at the end of 2006, 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 per cent on defending the World Championships next year."
McLaren 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.
"We always make it clear that we want to be the best and the only way of achieving this objective is by attracting the best people, the best drivers and the best sponsors. To be able to announce Vodafone as only McLaren's third title partner in more than 30 years and Fernando's employment within only a few days is fantastic news for the team, our Partners, Formula One and the fans."
The contracts of McLaren's drivers Juan Pablo Montoya and Kimi Raikkonen are both up for renewal at the end of the season and the team are is talks with both of them about their future deals. Raikkonen has already been linked with a switch to Ferrari in 2007.
Dennis 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."
Mercedes-Benz motorsport boss Norbert Haug added: "We are pleased to welcome Fernando to the team and look forward to working both with him and our new title sponsor in 2007.
"To have a World Champion joining the team is a great endorsement and will create a tremendous amount of excitement. However for now our focus must remain on the 2006 season where we want to go one better than we did in 2005."
Renault have not yet commented on Alonso's decision but they are expected to do so later today.
Subscribe to Autosport Plus
Register for free