Tomas Ujfalusi has signed a three-year contract to join Atletico Madrid from Fiorentina on a free transfer.
The Czech Republic defender had been linked with a string of leading European clubs after turning down a new deal at Fiorentina.
Atletico had always been tipped as favourites to capture the centre-half and have now confirmed the move has been finalised.
Ujfalusi spent four seasons with Fiorentina and made over 120 appearances in Serie A after joining from Hamburg.
He was the Czechs' captain at Euro 2008, but was unable to lead his national team beyond the group phase in Austria & Switzerland.