Fernando Alonso is to return for a second attempt to win the Indianapolis 500 next year.
The Spaniard will drive a McLaren car, as he did on his Indy 500 debut in 2017, when he led 24 laps before retiring with engine failure.
The two-time world champion is leaving Formula 1 at the end of this season and has set his sights on winning motorsport's informal 'triple crown'.
He won the Monaco Grand Prix twice, and added the Le Mans 24 Hours this season.
Only Graham Hill has ever won all three prestigious races - the Monaco Grand Prix, Le Mans and the Indy 500.
Alonso, 37, said: "I've made clear for some time my desire to achieve the triple crown. I had an incredible experience at Indianapolis in 2017 and I knew in my heart of hearts I had to go back if the opportunity was there.
- McLaren's Spanish driver to retire from Formula 1 at end of season
- 'Fernando Alonso is an unbelievable talent - F1 will be a poorer place without him'
"I'm especially glad to be returning with McLaren. This was always my first choice if the team decided to do it, so I'm delighted they've decided to go ahead.
"It's a tough race and we'll be up against the best, so it will be a huge challenge. But we're racers and that's why we race. One of the things I'm looking forward to most is seeing the fans again, who are absolutely fantastic."
McLaren chief executive officer Zak Brown said: "We are relishing our return to the Brickyard and this incredible race. McLaren has a long and fond relationship with the Indianapolis 500 and it's a case of unfinished business for us with Fernando.
"No Indy 500 is a cakewalk; it's a massive challenge. We have the utmost respect for the race and our competitors. So, we are under no illusions. But McLaren are racers first and foremost, as is Fernando. We're going for it."
McLaren have not confirmed the team that will run the McLaren entry.