Collet will pilot the No. 18 entry for the defending two-time champions, who now fields 10 drivers for the upcoming season that begins March 10 on the Streets of St. Petersburg, Florida.
Last month, the 21-year-old Brazilian was also revealed as the reserve and simulator driver for the Nissan Formula E Team.
“The NTT IndyCar Series is a goal of mine for the future but right now, I am 100 percent focused on Indy NXT with HMD Motorsports,” said Collet.
“I have a lot to learn, and I am thankful for the opportunity. I will put my best foot forward at achieving race wins, podium results, and the championship for both HMD Motorsports and myself.”
A former Alpine Academy member, Collet comes in with six years of experience in the junior formula ranks, which features resume that includes winning the 2018 French Formula 4 Championship. He spent the past three season in Formula 3, scoring three victories, 11 podiums and one pole, along with a best championship result of eighth (2022).
Collet received his first taste of Indy NXT machinery with HMD last October in the Chris Griffis Memorial Test at the Indianapolis Motor Speedway road course, ending the day fifth. He returned with the team in November for a series test at Barber Motorsports Park and finished second on the timesheets.
“It has been a long process to officially confirm Caio as an HMD Motorsports driver in 2024,” said HMD Team President Mike Maurini.
“While he will also have the title of Reserve and Sim Driver for Nissan in Formula E, Caio’s main focus will be Indy NXT with us in 2024.”
