In a period of stringent exclusivity contracts, Fernando Alonso's bold decision to contest the Indy 500 is a great outlier and one which will be interesting to watch.
Back in the 1960s, many Formula 1 drivers crossed the Atlantic to tempt fate and a chance to win the coveted race, part of a historical Triple Crown which includes the Monaco Grand Prix and the Le Mans 24 Hours.
It's an unofficial achievement in motorsport, but the only driver in history to win the Triple Crown is Graham Hill.
Jim Clark won the Indy 500 in 1965 but never triumphed - oddly - in the glitzy Principality or at Le Mans.
In recent times, Juan-Pablo Montoya is the only man to have come close, clinching two wins at Indy and one in Monaco in 2003.
Mario Andretti regularly raced at the Indy 500 during his F1 years in the late seventies - early eighties, and Peter Revson dovetailed his F1 commitments (with McLaren) with an Indycar programme, or USAC as it was called back then.
Clay Regazzoni also scrapped the Monaco Grand Prix in 1977 to race at the Brickyard.
But the very last active F1 driver who won himself a spot on the famous 33-car Indianapolis grid was Brabham's Teo Fabi in 1984.
Nigel Mansell , who quit F1 in 1993 to successfully race in America, did a sort of reverse move, coming back to F1 for a four-race stint with Williams following the tragic death of Ayrton Senna.
It's a shock decision by Alonso, but it's always good to shake things up and we should be delighted with the Spaniard's 'go big or go home' attitude!
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