Crvena zvezda came to an agreement with Real Sociedad de Fútbol over the permanent transfer of defender Srđan Babić.
Young defender, who has been with the red-and-whites since last summer on loan, has now signed a four-year permanent contract with the Belgrade club.
The fee agreed is €800K. The clubs have agreed the payment should be made in four installments.
Babić, world champion with Serbia U-20 national team, will officially sign the contract on Thursday when the team returns to Belgrade from Cyprus.