The team had previously announced that another son of a famous father, Marco Andretti, will drive alongside Todd Kelly in car #7.
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Rahal moved to the IndyCar Series in 2008 after a single year stint in Champ Car, famously taking victory on debut at St. Petersburg to become the youngest winner of a major open-wheel race in history.
“I want to win,” he added of his goal for the event.
“That's what we go racing for. Certainly a top 10 would be awesome and getting back in the race for 2013 would be ideal!”
Kelly meanwhile enthused over having members of two of motor racing's most famous families join his team.
“Jack Daniel's Racing has secured two of the biggest names in American racing, Andretti and Rahal, and I am confident Graham will do an outstanding job for us,” said Kelly.
The signings are understood to have been orchestrated by the team's performance director Tony Dowe, whose resume includes an Indianapolis 500 victory as chief mechanic to Johnny Rutherford in 1980.