Lewis Hamilton
The youngest ever Formula One World Champion
Hamilton began karting in 1993 at the age of eight, at the Rye House Kart Circuit and quickly began winning races and Cadet class championships. At the age of ten he approached McLaren F1 team boss Ron Dennis for an autograph, and told him, “Hi. I’m Lewis Hamilton. I won the British Championship and one day I want to be racing your cars.” Dennis wrote in his autograph book, “Phone me in nine years, we’ll sort something out then.”
From the Cadet ranks, he progressed through to Junior Yamaha (1997) and Ron Dennis actually called him in 1998 after Hamilton won an additional Super One series and his second British championship. Dennis delivered on his promise and signed Hamilton to the McLaren driver development program. This contract included an option of a future F1 seat, which would eventually make Hamilton the youngest ever driver to secure a contract which later resulted in an F1 drive.
Source: Wikipedia

