Atletico seal deal for Elias
The 25-year-old, who was presented at Atletico's Calderon stadium, has already begun training with his new team mates and could make his debut on Monday at home to Racing Santander.
Elias said former Brazil internationals Roberto Carlos and Ronaldo, who both played for Real Madrid, had encouraged him to make the move to Atletico.
"I always wanted to play for a Spanish team and Atletico is a great European club," he told a news conference.
"I work a lot for the team and my preferred position is centre midfield," he added.