Jesper Gronkjaer has completed his move from Birmingham to Atletico Madrid after passing his medical on Tuesday.
"I'm very happy finally to be here in Spain after all the speculation," said the Danish international.
"I know Atletico Madrid is one of the best Spanish clubs. It's doing well and I want to be part of it"
Gronkjaer, who has agreed a contract until the end of the 2007 season, should be available to make his debut against Real Madrid on 9 January.
Gronkjaer joined Birmingham from Chelsea in July after scoring 11 goals in 119 appearances for the London club during a four-year spell.
But he failed to secure a regular first-team place at St Andrew's and became a target for criticism from the club's fans.