And the impatient champion said he "ca't wait" to try his new McLaren MP4-25 when Formula One testing gets under way in February 2010.
Jenson Button, officially now a McLaren driver, added: "It is fantastic to be part of one of the most famous names in F1."
"There are a lot of new faces to remember and lots of names to learn - and that's all got to be done parallel the engineering and limited testing we have ahead of the 2010 season.
Jenson Button described the wait to start testing as a "mixed blessing".
"Honestly, I really ca't wait to get out to Valencia and get my first run in the MP4-25. I think that's when it will finally sink in that I'm a McLaren driver."
And like Button, he has only one aim in mind - the world championship.
The 2008 champion said: "You can never take competitiveness for granted in F1 - we saw that in 2009. So our common aim has to be to make MP4-25 a winning proposition as quickly as possible.
F1 supremo Bernie Ecclestone reckons Sebastian Vettel - and not Michael Schumacher - will be Germany's next world champion.
And he believes the 22-year-old Red Bull ace - second to Jenson Button in 2009's title race - could even do it in 2010.
Ecclestone admitted he was "very, very happy" about Schumacher's come back to the Grand Prix grid with Mercedes.
But he added: "I'm saying it well in advance, but for me, Sebastian Vettel will be the next world champion.
