Dean Stoneman will switch to America for 2016 and contest Indy Lights with IndyCar powerhouse Andretti Autosport.
Stoneman won the 2010 Formula 2 title before his career was interrupted by treatment for testicular cancer.
He subsequently returned to racing in Britain's Porsche Carrera Cup in 2013, before finishing runner-up to Alex Lynn in the '14 GP3 Series and racing in Formula Renault 3.5 with Red Bull backing last year.
Team boss Michael Andretti described Stoneman as a "true raw talent" with "an incredible, inspirational story."
He added: I can't think of a better fit for our Indy Lights team and the Mazda Road to Indy programme for the 2016 season."
Stoneman had previously tested Andretti's Lights car in 2012.
"We have been looking at racing here for a while now and to have finally secured a seat with Andretti in Indy Lights is a fantastic move for me," said the 25-year-old Briton.
"This season will form the first step towards racing in the IndyCar Series.
"One of the motivating factors of coming here is the the Mazda Road to Indy programme.
"Rewarding success and assisting progression to the next level of the sport is great and can make a huge difference to a driver's long-term career in racing."
He will begin testing with Andretti at Phoenix this week, in a run that will mark his oval debut.
Stoneman's Lights move comes a day after the announcement that European Formula 3 champion Felix Rosenqvist would join the series with the Belardi Auto team.
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