O’Ward will contest FP1 at this weekend’s Abu Dhabi Grand Prix season finale in place of Lando Norris, with McLaren complying with FIA regulations by running a rookie driver in both of its cars.
But that will be the only change McLaren has to field for a practice session this year since Oscar Piastri, completing his maiden F1 season, qualified as a rookie for the opening Bahrain and Saudi Arabian GPs.
O’Ward, who finished fourth in the 2023 IndyCar standings for the Arrow McLaren team, also contested FP1 in Abu Dhabi last season where he was 18th fastest, having only completed 22 laps due to a technical fault.
The Mexican will also remain at the Yas Marina circuit to conduct the post-race test next week.
McLaren F1 team principal Andrea Stella said: “Pato had an impressive season in the IndyCar Series and has performed well in his driver development tests, so it felt natural to take this next step now he’s eligible for an FIA Super Licence.
“With the expansive calendar, it’s prudent to ensure we have a wide pool of drivers that we can call upon if required. We look forward to seeing him progress in this new role.”
Owing to an agreement with power unit supplier Mercedes, McLaren can also call upon the Three-Pointed Star’s reserve Mick Schumacher, who will remain in his F1 role in 2024 while he contests the World Endurance Championship for Alpine.
This season, McLaren has also been able to use Aston Martin (also a Mercedes customer) reserves Stoffel Vandoorne and Felipe Drugovich.
O’Ward added: “I’ve spent a lot of time with the F1 team having driven previously in free practice and taken part in a few tests.
“I’ve always said it's never a bad day when you get to jump into an F1 car, so I look forward to joining the reserve driver pool for next year alongside my driving duties with Arrow McLaren.”
O’Ward effectively replaces two-time IndyCar champion Palou as a reserve as the McLaren Racing company has sued the Spaniard for prematurely cutting ties in a case rumoured to be worth over $20million.
McLaren and Chip Ganassi Racing driver Palou agreed a contract for 2024, but the driver reneged on this.
Reputedly, a McLaren deal would have given Palou a route to a full-time F1 seat, but this was then effectively closed off due to the impressive rookie performances from Piastri, who has since signed a new contract that will keep him at the team until the end of 2026.
