Button, 43, will be piloting the No. 15 Rick Ware Racing Ford Mustang with support from Stewart-Haas Racing. Mobil 1 will serve as the primary sponsor on the car.

2007 F1 world champion Kimi Raikkonen will also be racing at COTA, driving a third entry for Trackhouse Racing.

Along with COTA on March 26, Button will also compete at the Chicago Street Course race on July 2 and at the Indianapolis Motor Speedway Road Course on August 13.

COTA will be Button's first appearance in any division of NASCAR and comes just a few months ahead of the 24 Hours of Le Mans, where he will share a modified Next Gen Cup car alongside Jimmie Johnson and Mike Rockenfeller. That car is being prepared by Hendrick Motorsports.

Jenson Button, Rick Ware Racing Ford Mustang

“The first time I jumped into the Garage 56 car, it was like, ‘What have I done? This is so different,’ and that lasted about four laps. Then it was like, ‘Hang on, it’s still a racecar. It’s got four tires that touch the road. It’s a mechanical racecar, which is even better for learning.’ I’ve really enjoyed the challenge,” said Button, who has now tested the Garage 56 car at Sebring (Fla.) International Raceway, Daytona (Fla.) International Speedway and earlier this week at COTA.

“A Cup car has a lot less downforce and is a lot heavier, but the Garage 56 car has given me an idea of what it will be like along with a direction, which is really useful. I know in my first race I’m not expected to be qualifying right at the front and I’m not expected to be fighting for a victory. I have a lot of respect for the drivers racing in the Cup Series. There’s so much talent there, whether it’s on ovals or road courses.

“Ten years ago, people used to say NASCAR guys can’t drive around a circuit, but I think they’ve proven that they can. Every time an ex-F1 driver gets in a stock car these days, they struggle initially. It takes a while for them to get up to speed, so I don’t expect to be right at the front, straight away. That’s why, for me, doing more than one race is really key so I can get the best out of myself and the best out of the car.”

Button has 306 starts in Formula 1 with 15 victories, 50 podiums, and eight pole positions. His last start came in the 2017 Monaco Grand Prix, subbing for Fernando Alonso at McLaren while he was attempting the Indianapolis 500.

After retiring from F1, he went on to win the 2018 Super GT title in the GT500 class.

Jenson Button, Rick Ware Racing Ford Mustang

“The reason I was able to stay in Formula One for so long was because I always felt I was learning," said Button. "There was always something new in terms of technologies, or I could still improve my driving or engineering skills within Formula One. When I got to my 17th year in F1, I felt like I lost that hunger a little bit because it wasn’t new anymore. There wasn’t something new to learn.

"Stepping away from F1 gave me the opportunity to try different series that excited me. I raced Super GT in Japan. I raced at Le Mans. I raced off-road because it was another skill to learn. You put yourself in a slightly vulnerable position because it’s not your complete skill set, and there’s still more to learn to be as good as the best. I love that challenge of driving new things. It’s slightly out of my comfort zone, and I found that out with off-road trucks.

“Obviously, racing a Cup car is very different than what I’m used to. It’s a lot heavier with a lot less power and, basically, no downforce. It’s got a sequential gearbox where you need to blip the throttle, so there’s lots of stuff to learn in a very short space of time. “But I just get excited about that new challenge, and when I throw myself into something, I am 100 percent in. I’m not just doing it for fun in some one-off. I want to be competitive, and I know that to be competitive, it’s going to take a bit of time. That’s why doing these three races works very well this season.”

COTA will also feature the NASCAR Cup debut of accomplished sports car racer Jordan Taylor, who will be subbing for an injured Chase Elliott behind the wheel of the No. 9 HMS Chevrolet.