The McLaren MP4-21 is a Formula One car that competed in the 2006 Formula One season. It was driven initially by Kimi Raikkonen and Juan Pablo Montoya. After ten races, reserve driver Pedro de la Rosa took over Montoya's race seat. Gary Paffett was also a test driver for the MP4-21. Future World Champion Lewis Hamilton drove the MP4-21 in his first official Formula One test in September, 2006 prior to joining McLaren for 2007.