McLAREN have announced the signing of reigning Formula One world champion Jenson Button.

The 29-year-old will form an all-British driving partnership with former world champion Lewis Hamilton for the 2010 season.

Button has left reigning constructors champions Brawn GP, who were the subject of a takeover by Mercedes-Benz earlier this week.

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, and is the first pairing of British champions since Graham Hill partnered Jim Clark at Lotus in 1968.

Button, who has reportedly agreed a three-year deal worth £6million a season, moves to the Woking-based team after a glittering campaign with Brawn that delivered six grand prix wins and his maiden world title.

"It's always a difficult decision to leave a team when you've been there for so long," said Button. "But life is all about challenges - and, most important of all, it's about challenging yourself.

"So, although I won the World Championship with Brawn GP last year, and I'll never forget that, I was always adamant that I wanted to continue to set myself fresh challenges.

"McLaren is one of the greats of world sport, and its achievements and list of past champions read like a Who's Who of Formula One - Emerson Fittipaldi, James Hunt, Niki Lauda, Alain Prost, Ayrton Senna, Mika Hakkinen and, of course, my new team-mate, Lewis Hamilton.

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

Hamilton, who won the world title with McLaren in 2008 in only his second season in F1, said: "It's fantastic news that Jenson has decided to join but I also want to send my best wishes for the future to my 2008-09 team-mate and now good friend Heikki Kovalainen, who is one of the nicest human beings I've ever met.

"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.

"He's an exceptional driver: very controlled and very smooth, and he has a real depth of knowledge and experience. I think we'll complement each other very well."