Button to partner with Hamilton

The multi-year deal completes an astonishing year for 29-year-old Button, who did not know if he had a future in the sport last December when his then-employers Honda pulled out.

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

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

Kimi Raikkonen, meanwhile, decided to take 2010 off after failing to sign a contract.