While all the focus will be on Cristiano Ronaldo and Lionel Messi in El Clasico, it will be Luis Enrique's last as coach of FC Barcelona, and he is one of the most famous El Clasico double agents – here are nine others, including a Brazilian World Cup winner and an African.
Tired of reading? Click through the gallery to see 10 famous El Clasico double agents and the number of trophies they won with each club.
Luis Figo is probably the most controversial El Clasico double agent, after a pig's head was thrown in his direction following his controversial move from the Catalan giants to Los Blancos.
However, he is also one of the most successful players to have played for both clubs. The Portuguese won seven trophies at the Camp Nou and another seven at the Santiago Bernabeu.
Enrique himself won three trophies while donning the Real shirt, before switching allegiances and later claiming another seven titles with Barca.
In fact, many of the El Clasico double agents won more trophies with Barca than during their stint at Real – Albert Celades (seven trophies at Barca, six at Real), Michael Laudrup (nine at Barca, one at Real) and Bernd Schuster (eight at Barca, four at Real) are other examples.
One of the few El Clasico double agents who lifted more titles for the Madrid club than the Blaugrana is Brazil legend Ronaldo de Lima. He won three titles in his sole season at the Camp Nou, and later claimed four trophies during five injury-laden seasons with Real.
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Samuel Eto'o also receives an honorary mention. The retired Cameroon captain made seven appearances as a teenager for Real, although he did not run out in an El Clasico and did not win any trophies at the Santiago Bernabeu. He later became one of Barcelona's most lethal strikers and won eight accolades during his time with the Catalan giants.
Which player do you think could become the next El Clasico double agent? Have your say in the comments section.
