The LMGT3 category replaces the LMGTE class that has been on the grid since 2012.
Nine-time world champion Rossi, who also owns the VR46 MotoGP team, will be making his Le Mans 24 Hours debut next June. This year the Italian won a Road to Le Mans support race.
Polish former Formula One driver Robert Kubica (38) will be driving a Ferrari in the top Hypercar category of the championship with the AF Corse team after winning the now-defunct LMP2 category.
Mick Schumacher (24), a Mercedes F1 reserve driver and son of Ferrari great Michael, will be making his Hypercar debut in the series with Renault-owned Alpine.
Championship organisers published the entry list on Monday with a record 19 Hypercars and 14 manufacturers represented across both classes. The LMGT3 class has 18 entries.
The manufacturers are Alpine, Aston Martin, BMW, Cadillac, Corvette, Ferrari, Ford, Isotta Fraschini, Lamborghini, Lexus, McLaren, Peugeot, Porsche and champions Toyota. Nine of them will be competing in the Hypercar championship.
McLaren have partnered with United Autosports to make their LMGT3 debut.
"To have an entry list featuring 19 Hypercars plus 18 LMGT3 entries representing 14 different manufacturers truly reflects the golden era of endurance racing that we are experiencing right now," said WEC chief executive Frederic Lequien.
