Paris Saint-Germain defender Yuri Berchiche has joined Athletic Bilbao.
The two clubs confirmed the deal on Monday morning with a four-year contract signed, including a €100m release clause, but no fee or further details have been mentioned.
Berchiche left Real Sociedad for the French capital last summer in a €15m move.
Berchiche scored two goals and provided five assists in 32 appearances for the Parisians since his move from La Real to the Ligue 1 champions last summer.
The defender has become the second former La Real defender to join their Basque rivals following Inigo Martinez's €32m switch in January.