Plans for the regulation change, exclusively revealed by Autosport in March, were confirmed by WEC organisers the Automobile Club de l’Ouest and the FIA at the former’s traditional Friday press conference ahead of this weekend’s Le Mans 24 Hours round of the WEC.
The chairman of the FIA's Endurance Commission Richard Mille said: "It makes sense for a world championship. Each manufacturer should have two cars.
"We want manufacturers to bring something serious. Another factor is the Balance of Performance, you need the data of two cars."
The new rule will go hand in hand with an expansion of the WEC grid from 37 cars to 40 for 2025.
Series boss Frederic Lequien revealed the 40-car target last year and this was also confirmed at the press conference.
The Hypercar manufacturers that will have to react to the two-car rule are Cadillac, Lamborghini and Isotta Fraschini, which are all running solo cars this year, and 2025 newcomer Aston Martin.
Aston announced one-car entries with a non-hybrid prototype to be known as the Valkyrie AMR-LMH in both WEC and the IMSA SportsCar Championship on the launch of the project last October, but stressed last month that its plans would not be derailed by any rule change.
It has now put out a statement, timed to coincide with the ACO press conference, confirming the intent for its factory Heart of Racing team to field a pair of Valkyries in WEC.
Adam Carter, Aston’s head of endurance motorsport, said: “In 2025 with our works team Heart of Racing, we intend to put two Aston Martin Valkyrie AMR-LMHs on the grid to compete alongside a fantastic array of the world’s best sportscar manufacturers.”
Laura Wontrop Klauser, head of sportscar racing at Cadillac parent company General Motors, told Autosport that the marque will “react to the regulations as they come”.
It looks certain that the British Jota team will swap over from customer Porsche 963 LMDhs to become Cadillac’s factory team running two V-Series.Rs next year.
Lamborghini, which is represented by the Iron Lynx team, outlined an intent to go to two cars in WEC in 2025 as long ago as the launch of the car last July, while Isotta Fraschini, which joined the WEC this year in conjunction with the French Duqueine team, has also spoken about its expansion plans.
Claudio Berro, motorsport boss at Isotta, explained that the priority is to work with Duqueine on a second Tipo 6 Competizione LMH.
“It is not in our mind to look for another team at the moment,” he told Autosport.
