Since Barca were founded in 1899, over 30 players have appeared for both clubs, although no player has directly switched between the rivals for 15 years.
Javier Saviola was the last to do so, but Real’s Isco could soon do the same after reportedly agreeing personal terms with Barca.
With Isco potentially set to become the latest player to play for both clubs, here are seven others who have played for both Real Madrid and Barcelona.
Arguably the most controversial instance of a player moving between Barcelona and Real Madrid, Portuguese midfielder Luis Figo made the switch in 2000.
He had been a fan favourite at the Nou Camp after winning two league titles, but any love for him was extinguished when he left for Real Madrid.
Figo infamously had a pig’s head thrown at him, among other objects, while taking a corner on one return to the Nou Camp in 2002.
Overall, Figo made over 200 appearances and won multiple league titles for both clubs but is remembered far more favourably by those in Madrid.
Figo was joined at the Santiago Bernabeu by Brazilian striker Ronaldo in 2002, having played together for just one season in Barcelona in 1996/97.
Ronaldo scored 47 goals in 49 matches that season and won the Ballon d’Or following his move from Barca to Inter Milan thanks to those goals.
After joining Los Blancos, the mercurial forward won another Ballon d’Or as well as two La Liga titles before injuries curtailed his time at the Santiago Bernabeu.
Unlike Figo, Ronaldo is still viewed fondly by fans of both clubs.
Former Denmark midfielder Michael Laudrup won four consecutive league titles in the early 1990s as part of a Barcelona side managed by the late Johan Cruyff.
He later moved to Real following a falling out with Cruyff and went on to win another league title in his first season with his new club.
Laudrup also has the distinction of being on the winning side in two 5-0 El Clasico wins, one for each side, which came in his last season at Barca and first at Real Madrid.
Although he only spent two seasons at the Bernabeu, Laudrup was voted as the 12th best player in Real Madrid’s history in a Marca poll in 2002.
Luis Enrique had spells with Barcelona as both a player and a manager, having also captained the Blaugrana during his playing career.
Prior to joining Barca, though, he spent five years in Madrid, where he won three trophies including one league title.
It was at the Nou Camp where Enrique would become a legend, though, becoming a beloved captain and scoring in five times in Clasicos.
He returned to Barca as manager in 2014 and went on to win two league titles to add to his two as a player as well as the Champions League in his first season in charge.
Samuel Eto’o managed just seven appearances for Real Madrid after joining the club’s academy at the age of 15, before rising to prominence at Mallorca.
His form for the island club earned him a move to Barca in 2004 and he went on to score over 100 goals for the club in five years at the Nou Camp.
This included scoring in two victorious Champions League finals as well as winning three league titles to show Real Madrid what they had missed out on.
Romania legend Gheorghe Hagi failed to win a league title or Copa del Rey across his combined four seasons with Real Madrid and Barcelona.
He regularly provided flashes of brilliance and stunning goals after joining Real off the back of a breakthrough tournament at Italia 90.
Hagi only won one Spanish Super Cup with the club in two seasons before leaving for Italy, but he returned to Spain with Barca two years later.
Again, the talented playmaker was only able to win the Super Cup during two seasons with Barca between 1994 and 1996.
Another talented playmaker who was unable to replicate the trophy-laden spells with Barca and Real that others on this list did is Robert Prosinecki.
The Croatian joined Real Madrid in 1991 and scored in El Clasico during a first season severely hampered by injuries, but became a key man in the next two campaigns.
He won the Copa del Rey and Spanish Super Cup with the club before later moving to Barca after one season with Oviedo.
His time at Barcelona was again disrupted by injuries as he failed to establish himself as a regular starter in just one season with the club in 1995/96.