Sunderland have signed centre-back Frederik Alves on a season-long loan deal from Premier League side West Ham United.
The 21-year-old joined the Hammers for an undisclosed fee in January from Danish side Silkeborg IF.
"I'm looking forward to learning the English style of play and playing matches," he told the club website.
"The fans can expect a football-playing centre back - I like to play football a lot - but I'm also a physical player."