The report added Perez wants to set an all-time record attendance for tennis at Real's 81,044-seater stadium in the Spanish capital.
The current record is the 35,681 who watched an exhibition match between Kim Clijsters and Serena Williams in Brussels in 2010.
Nadal and Federer, though, are already part of a plan to beat that mark on February 7, 2020, at the Cape Town Stadium in South Africa, which holds 55,000 spectators, per Reuters.
Arguably the two greatest players to ever wield a racket, Nadal moved to within one of Federer's all-time Grand Slam record when he won the U.S. Open last weekend:
The 33-year-old Spaniard beat Russia's Daniil Medvedev 7-5, 6-3, 5-7, 4-6, 6-4 at Arthur Ashe Stadium in New York.
He will have the chance to join Federer, 38, on 20 Grand Slam titles at the 2020 Australian Open, which starts in January.
Nadal's only previous triumph in Melbourne was in 2009, making it his least productive Grand Slam tournament, as he has won Wimbledon twice, the U.S. Open four times and the French Open a record 12 times.
By contrast, Federer is a six-time Australian Open champion, and he will likely be viewing 2020's opening Grand Slam as a good opportunity to further open the gap between him and Nadal.