Atlétic have confirmed the signing of Manolo Galliani from Real Madrid.
The 22-year-old will join the Spanish side on a free transfer after the summer transfer window opened.
The former Chelsea defender has made a total of 28 appearances for the Spanish giants, scoring three goals.
He has also started 11 games for the club this season, scoring twice.
“We’re very happy to bring a player of his calibre to the Club Atlética,” Atlétics general manager Fernando Siqueira told AtlétiMercato.
“The player we have is one of the best in the world and has been a member of the squad for two years.
We’re happy to add a player that is a great addition to our squad.”
Atlético’s current squad includes a number of international stars, including Diego Costa, Sergio Ramos, Alvaro Morata, Fernando Llorente, Cristiano Ronaldo, Dani Alves, James Rodriguez, Carlos Tevez, Karim Benzema, Mario Mandzukic and Gonzalo Higuain.