Malukas has been unable to drive competitively since sustaining a wrist injury in a mountain biking accident on 12 February. He was replaced by Ilott at the subsequent tests and in the season-opening Grand Prix of St. Petersburg, where the 25-year-old Brit finished 13th.
As Malukas carries on with his recovery, Ilott will again drive one of Arrow McLaren's Chevrolet-powered entries in the upcoming Barber test, as well as in the non-championship $1 Million Challenge.
The event is taking place on 24 March at private motorsport facility The Thermal Club, located in southern California, fewer than 150 miles away from Los Angeles.
The 17-turn, 3.067-mile track will host an open test and qualifying on 23 March before the race that Sunday. While points are not on offer, the winner will take a coveted one-million-dollar prize.
A former European F3, GP3 and Formula 2 frontrunner who made his IndyCar debut in 2021 with Juncos Hollinger Racing, Ilott lost his drive with the Argentine-American squad to Romain Grosjean at the end of last year.
"I was expecting to stay in IndyCar, that was the original plan, and circumstances changed as they sometimes do in life," the Englishman said at the time, having managed two top-five finishes as his best results over that period.
This development made him an ideal stand-in for IndyCar outfits in 2024 while he focuses on his main racing programme in the WEC, hence this opportunity with Arrow McLaren.
“To be honest, it's a bit of a discovery process because obviously I did the hybrid test, but I've only been in the shop for one or two days now,” the former JHR driver said last week, ahead of the first round of the campaign.
“The size of the team obviously is larger, and more years of experience within the series, but I can't really comment on that until during the race weekend and experiencing it on that side of a full scale. Obviously, it's great. The preparation is good even though I've had to be in Qatar and full focus on that. But now it's obviously full focus on St. Pete.
“That's increasing and ramping up, and I'm excited to see what the full scale of the operation is.”
Recently asked by Motorsport.com about the number of IndyCar events he could do alongside his Hypercar commitment, Ilott responded with 11-12 races "if I had to".
In WEC, Ilott shares a Porsche 963 entered by Team Jota with team-mates Norman Nato and Will Stevens. The Anglo-French trio achieved a second-place finish in the first round of the campaign, the Qatar 1812Km.
Additional reporting by Joey Barnes and Charles Bradley
