Derby have signed Raul Albentosa for an undisclosed fee from La Liga side Eibar on a two-and-a-half-year deal.
Head coach Steve McClaren confirmed Derby's interest in the 26-year-old earlier in the week.
Centre-back Albentosa, who is 6ft 5ins, made 17 starts this term after helping the Spanish club reach the top flight for the first time.
McClaren told the club website: "He's shown a real desire to come here and be part of what we are trying to achieve."
The defender's former club posted on Twitter on Thursday evening: "Raul Albentosa has paid today the termination clause of his contract and ceases to belong to the SD Eibar."