Double Formula One world champion Fernando Alonso sees next month's Indianapolis 500 as a bigger challenge than the Le Mans 24 Hours sportscar race as he seeks to win motorsport's famed 'Triple Crown'.

"The biggest task is definitely the Indy 500 for a Formula One driver," the Spaniard told reporters on a visit to Barber Motorsport Park on Sunday.

"I think it's quite different. It's challenging ... the level of downforce, the feeling with the car, running with a car that is not symmetric on the straights, on braking. Traffic I think is a big thing..."

McLaren have since announced that former IndyCar champion Gil de Ferran has been drafted in as a mentor for the Spaniard.

Alonso said De Ferran, winner of the Indy 500 in 2003 and a two-time IndyCar champion, would "coach" him.

The French-born Brazilian told BBC Sport: "I will try to mentor him through his introduction to the speedway and its nuances."

Alonso has set his sights on becoming only the second driver after the late Briton Graham Hill to win the Formula One championship, Indy and Le Mans.

The McLaren driver, who will miss the showcase Monaco Grand Prix to race at the famed Brickyard on May 28 for the first time, has no experience of Le Mans either but indicated that would have to wait until after Formula One.

Gil de Ferran with his family in 2009 following his final race before retirement (Getty)

The 35-year-old felt that French race, won by current Renault F1 driver Nico Hulkenberg with Porsche in 2015, would be an easier leap because the cars were more similar.

"Some of the F1 drivers that jump into the Le Mans car, they have no difficulties in terms of adapting," said Alonso, whose current McLaren contract expires at the end of the year.

"The 24 Hours is a little different, it's a more relaxed race, you can do it at an older age," added the Spaniard, a friend of Australian former F1 driver and now-retired Le Mans racer Mark Webber.

Alonso was in Alabama with McLaren boss Zak Brown, who said he would like to see a McLaren-Honda competing at Indianapolis every year, to meet the Andretti Autosport Team who will run his Indy car.

Alonso also has his sights set on Le Mans (Getty)

"I'm with the best team possible for this type of lessons that I need to learn. I'm also with coach (and 2003 Indy winner) Gil de Ferran, which I'm sure will be very, very useful for all these new things that I need to learn," he said.

McLaren won Le Mans in 1995 but Brown said it was "very early days" to contemplate a return.

"Our automotive group will make the decision. Mike Flewitt, the CEO of McLaren Automotive Limited, would make the ultimate decision ... but nothing has been discussed. I think Le Mans is a massive race like the Indy 500," he said.