The game is being played at the FNB stadium, formerly known as the Soccer City stadium, where Spain won the 2010 World Cup with a team featuring Barca players Gerard Pique, Sergio Busquets and captain Andres Iniesta, who struck the only goal in their 1-0 win over the Netherlands.
"FC Barcelona has always professed its admiration for Nelson Mandela, one of the greatest figures of the 20th century, who after 27 years in prison went on to become the first democratically elected president of post-apartheid South Africa from 1994 to 1999," said a statement on the club's website.
"Mandela represented the struggle for freedom and equality in the country, and played a huge role in unifying the racially divided society. It is precisely this kind of spirit with which FC Barcelona has always been identified."
Mandela was born on July 18, 1918.
The friendly is sandwiched between Barca's penultimate Liga game away to Levante on May 13 and their final game at home to Real Sociedad on May 20.
Ernesto Valverde's side clinched a 25th Liga title on April 29 and the King's Cup on April 21 and are bidding to become the first team since 1933 to complete a Spanish top flight season without losing a game.
(Reporting by Richard Martin; Editing by Toby Davis)
