Button announced Wednesday that he had ended his long association with Brawn, with whom he won his first driver's title this year, to team up with 2008 champion Hamilton in a combination of two of the hottest properties in motor sport.

Button said it had been a tough decision to leave Brawn but admitted the lure of McLaren and its illustrious history, had proved too strong to resist.

"I've followed the McLaren team ever since I was a small boy, and it feels unbelievable to finally be a part of it," he said.

The deal marks the first time in Formula One history that a team has started the new season with a line-up featuring the most recent two successive world champions.

It is also the first pairing of two British world champions since Graham Hill partnered Jim Clark at Lotus in 1968.

Brushing aside predictions of an Alain Prost/Ayrton Senna-style battle to be top dog within the team, Button insists he was looking forward to working with Hamilton.

"Lewis has achieved an incredible level of success in a very short period of time, and he's a wonderfully gifted driver who has earned the respect of every Formula One driver," Button said.

"I'm sure there's plenty that we can learn from each other, and I'm really looking forward to using our combined knowledge to push the team forward."

Hamilton added: "I already know Jenson, and we get on very well together. We both really want our team to succeed. Although we'll be pushing each other hard, I'm sure we'll very quickly establish a great working relationship."

Ross Brawn, the boss of Button's former team, had urged the 29-year-old not to jump ship. But there was uncertainty over the extent to which Mercedes, which acquired a 75 percent stake in Brawn GP earlier this month, was committed to keeping him.

Brawn will be rebranded Mercedes GP for the 2010 season and German Nico Rosberg has already been lined up as one of their drivers. Another German, Nick Heidfeld, is the favourite for the second seat.

Button's move to McLaren became possible after the team decided not to retain Heikki Kovalainen and then failed to reach an agreement with former world champion Kimi Raikkonen, who has decided not to race in Formula One next year.