McLaren's Fernando Alonso will compete in next January's Daytona 24 Hour sportscar race as preparation for an eventual tilt at Le Mans.
The United Autosports team owned by McLaren executive director Zak Brown announced the move on Friday.
Alonso, a double Formula One world champion who is competing in thisweekend's Mexican Grand Prix, made a big impression last May when he entered the Indianapolis 500 and led for 27 laps.
He has set his sights on becoming only the second driver, after Briton Graham Hill, to win motorsport's Triple Crown.
That entails winning the Formula One title, or Monaco Grand Prix according to other interpretations, as well as Indianapolis and Le Mans.
Alonso, 36, has won Monaco as well as his 2004 and 2005 world titles. He recently signed a contract extension keeping him at McLaren in 2018.
"The Daytona 24 Hours is the most iconic US endurance race and one of the world's great races. Everyone knows it," Alonso said.
"It's not part of the Triple Crown but, as I have always said, my aim is to be a complete driver and this experience will help me in the preparation for any other endurance race I might take part in.
"I am excited to go back and race in America.
"After the great time I had during the month of May for the Indy 500, I am looking forward to taking part in another legendary race that will bring back all those amazing sensations that US fans gave me."
Daytona comes before the start of Formula One's pre-season testing when drivers are mostly working on physical preparation for the year ahead.
Le Mans, on June 16-17, does not clash with any grands prix - unlike Indianapolis which is on the same weekend as the Monaco Grand Prix.
Alonso will partner British teenagers Lando Norris, the McLaren development driver tipped to take a reserve role next season, and Phil Hanson.
Daytona, in Florida, will be the first time the Spaniard has raced a prototype sportscar.
