The former Alfa Romeo Formula 1 reserve driver will race the British squad’s #12 Porsche 963 LMDh along with team regular Will Stevens and Norman Nato.
Ilott and Nato were announced on Monday by Jota for #12 in its expanded two-car Hypercar squad along with Phil Hanson, who will race the #38 car together with Oliver Rasmussen and a yet to be determined third driver.
Twenty-five-year-old Ilott landed the Jota drive after a successful test in the team's first 963 at Qatar at the beginning of this month.
“We’re very excited to have Callum in the car for next season,” Jota team principal Sam Hignett told Autosport.
“He tested with us in Qatar and he did the excellent job we were expecting.”
Ilott added: "I’m so excited to be racing a Porsche in the top-class with Hertz Team Jot. I had a two-day test recently and the car felt great and was enjoyable to drive.
“I’ve been ultra-impressed with the team, they’re incredibly professional, and I already know that with the Porsche, we’re going to be challenging for top results next season and hopefully success at Le Mans itself."
Ilott is switching to sportscar after splitting with the Juncos Hollinger IndyCar team for which he had raced since the end of 2021.
His previous sportscar experience came with the Iron Lynx Ferrari squad in 2021, the season in which he participated in a pair of Friday F1 free practice sessions at the wheel of the Ferrari-engined Alfa Romeo C41.
Ilott competed in the five-round GT World Challenge Europe Endurance Cup in a Ferrari 488 GT3 and also raced at the Le Mans 24 Hours, driving the GTE version of the car in GTE Am.
Frenchman Nato, who has switched from Nissan to Andretti Global for the 2023/24 FE season, joins the British team after a tryout in the official WEC rookie test in Bahrain the day after this season’s final round of the championship.
The Frenchman steps up to the Hypercar class three years on from a two-season stint with the Rebellion Racing LMP1 squad that yielded a pair of WEC victories over the 2019/20 season.
Hanson moves up to Hypercar after eight seasons in LMP2, including four in the WEC with United Autosports that yielded the class championship in his maiden campaign in 2019/20.
The Briton will dovetail the full-season drive in the WEC with an assault on the five IMSA SportsCar Championship enduros with the JDC-Miller Motorsport Porsche squad.
Stevens and Rasmussen were listed against the #12 and #38 Hypercar entries respectively when the WEC entry list was published late last month.
The announcement of Ilott, Nato and Hanson means there is now just one seat to be filled in Jota’s expanded two-car squad of Porsche 963s.
Yifei Ye, who had the backing of Porsche Motorsport Asia Pacific, is not expected to remain with Jota for 2024 and is tipped to race for the third Ferrari 499P Le Mans Hypercar fielded on a customer basis by AF Corse.
The Chinese driver would be renewing a relationship with Robert Kubica, a driver with whom he claimed the 2021 European Le Mans Series driving for the Belgian WRT squad.
Kubica was one of a trio of star, ex-Formula 1 names along with world champions Sebastien Vettel and Jenson Button who have been in negotiation with Jota for 2024.
The Polish driver subsequently opted to go with AF, while it is unclear whether Jota will be successful in its attempts to sign one of the former champions.
