Jenson Button vowed to make the United Kingdom proud after joining Lewis Hamilton at McLaren to form an all-British line-up.
McLaren yesterday confirmed the arrival of Button on a "multi-year deal", ending weeks of speculation over the future of the 29-year-old, who wrapped up his maiden world title in Brazil last month.
Button, who began his career at Williams in 2000 and has gone on to make 170 grand prix starts, will line up alongside Hamilton after parting company with Brawn GP, who were the subject of a takeover by Mercedes-Benz earlier this week.
Button's move to McLaren ends his seven-year association with the Brackley-based Brawn GP outfit, whom he joined in 2003 when the team was known as BAR before establishing himself as the team's number one driver prior to Honda's takeover in 2006.
Button is under no illusions about the task ahead, but nevertheless expects to form a formidable partnership with Hamilton.
"It's fantastic that we'll be forming an all-British line-up," he said.
"I know that we both fly the flag with pride and I sincerely hope we can make the whole of the United Kingdom, as well as Vodafone McLaren Mercedes fans across the world, proud.
"Nothing means more to me than to be able to represent my country.
"This is a team that always goes racing to win and I'm looking forward to being part of that."
The deal marks the first time in Formula One history that a team has started the new season with a line-up featuring the two most recent world champions, and is the first pairing of two British world champions since Graham Hill partnered Jim Clark at Lotus in 1968.
Button has reportedly agreed a three-year deal worth £6million a season, a figure which, if accurate, is far below what has been commanded by other world champions in recent seasons.
And McLaren team principal Martin Whitmarsh underlined the belief that Button's move from Brawn was not about the money.
"I want to make clear that Jenson's decision to join us was in no way motivated by money," said Whitmarsh.
"We'll be paying him no more than he could be getting elsewhere and that fact is a reflection of not only Jenson's belief in Vodafone McLaren Mercedes but also his desire and ambition to build on the phenomenal results he achieved during the 2009 season."
Button's new team-mate welcomed the arrival of his fellow Englishman while reserving special praise for the outgoing Heikki Kovalainen, his team-mate of the last two seasons who must now find a drive elsewhere.
Hamilton said: "It's fantastic news that Jenson has decided to join Vodafone McLaren Mercedes.
"I'm looking forward to working with him and our engineers to make sure we kick off the 2010 season with a car that's competitive enough to win the World Championship, but I 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."