When FC Barcelona host Atlético Madrid at the Camp Nou on Wednesday night, there will be few players who do not know each other well.
Despite being rivals at club level, 27 players from either side are teammates in their respective national sides. The country with the most players in common is that of Spain, with six from Barça (Piqué, Sergi Roberto, Alba, Busquets, Iniesta and Alcácer) and three from Atlético (Koke, Saúl and Juanfran).
Then there are handful of Frenchmen on opposite sides of the battle line, in Digne, Mathieu, Umtiti, Griezmann and Gameiro, as well as two Croatians, Rakitic and Vrsalijko.
Argentina is also well presented, as Barça duo Messi and Mascherano will square up against Albiceleste colleagues Gaitán, Augusto and Correa. Brazilians Neymar and Rafinha face Filipe Luis while Luis Suárez goes head to head with fellow Uruguayans Godín and Giménez.
While they will all be greeting each other before the game, it remains to be seen whether they will be as friendly by the final whistle in what promises to be another thrilling clash.