FORT WORTH, Texas -- Two-time Formula 1 champion Fernando Alonso was chatting with seven-time NASCAR Cup series champion Jimmie Johnson in January, and Alonso casually mentioned they should drive each other's cars.
Alonso soon learned about the determination of Johnson.
"I went after it hard right away. I wasn't going to let a passing comment slow me down," Johnson said Friday at Texas Motor Speedway.
Johnson worked tirelessly to make it happen after that conversation at a NASCAR media day where Alonso was present to promote the Rolex 24 At Daytona sports-car race.
The Hendrick Motorsports driver will spend Nov. 26 in Bahrain, driving a McLaren F1 car. Alonso will drive a Hendrick Motorsports car that competed in a race earlier this year.
Johnson and Alonso have posted videos over the past two months teasing the ride swap, but this isn't going to be just a few laps and go home. Johnson is going to London after the NASCAR finale Nov. 18 to spend time in the McLaren simulator and have a seat fitted.
An avid runner and biker, Johnson also has been working on his neck muscles in hopes he can drive all day. Jeff Gordon, who drove Juan Pablo Montoya's F1 car in 2003, told him that will be his biggest challenge.
"In talking with Gordon, he had the ability to run more laps in the setup they had, and his neck wouldn't let him," Johnson said. "Our cars, especially in the brakes, we do not create the G's. We only have a couple of road courses a year, so our neck muscles are pretty far behind."
Johnson will attend the F1 finale Nov. 25 in Abu Dhabi, and then they will head to Bahrain to run the next day. The Hendrick car was put in a container Oct. 2 to be shipped, with enough tires and equipment to run a full day. A crew of Hendrick mechanics will attend the test to work with Alonso.
Bahrain was chosen because one of McLaren's investors is an owner at the Bahrain track. Johnson hopes to even do some laps under the lights.
The downforce in the F1 car is about six times that of a NASCAR Cup car, Johnson said. The braking zones are much deeper toward the turn in an F1 car than in a stock car.
"It is the ultimate car," Johnson said about testing the F1 car. "That's by design what they've created for a vehicle. Our vehicles are much more entertainment-based, certainly a lot of fun to drive.
"But to feel the downforce of one of those cars has always been in the back of my mind. I've always wanted to experience it."
Hendrick Motorsports is paying the costs associated with getting the crew and the car to Bahrain, Johnson said. Zak Brown, who heads the McLaren F1 program, is a longtime marketing executive who has overseen several motorsports marketing campaigns in NASCAR.
"Zak's like, 'Heck yeah, this is a great idea.'" Johnson said. "We'll see what the total [cost] ends up at. If there are crashed cars, they might turn to the drivers and say, 'Hey, help out.'
"I'm not sure what Fernando is doing. I've offered to help Rick [Hendrick] in any way."
What does this ride swap mean? Johnson has a contract with Hendrick through 2020.
"I don't have anything inked for 2021, but a 45-year-old F1 driver, I don't think has ever happened," Johnson said with a laugh. "But I'll put that out there."
As far as Alonso, who is retiring from F1 racing after this season, Johnson doesn't see a full-time NASCAR deal in Alonso's future.
"Fernando has a huge interest in driving the Cup car," Johnson said. "He really does. We even offered him some ovals when this thing changed direction [of where it would happen] a few times.
"He preferred to do it on a road course. ... He has not led me to believe any of that [full-time NASCAR talk]. If I was in his shoes and had the opportunity to go drive an oval, I would have taken it if NASCAR was a destination for me."