Novak Djokovic and Rafael Nadal will play an exhibition match at Real Madrid's Santiago Bernabeu on July 14.
The charity event has been organised by the Realmadrid Foundation and the Rafa Nadal Foundation, with the proceeds set to help impoverished children use sport as a tool for social integration.
In a statement on their club website, Madrid said they hoped to attract a crowd in excess of 80,000 to witness the encounter between the world's top two players, which would set a spectator record for a game of tennis.
"The pitch at the Santiago Bernabeu will turn into a tennis court on July 14 for a charity match between Rafa Nadal and Novak Djokovic," the statement read.
"It will be organised by the Realmadrid Foundation and the Rafa Nadal Foundation, hoping to gather a record 80,000+ crowd and collect proceeds for projects developed by both foundations."