Greece defender Sokratis Papastathopoulos is joining Champions league finalists Borussia Dortmund from Bundesliga rivals Werder Bremen.
Dortmund said that it the 24-year-old has signed a five-year contract. The German giants also said the two clubs agreed not to disclose further details of the transfer deal.
Papastathopoulos joined Bremen from Italian club Genoa two seasons ago. He says he benefited from the time with Bremen and added: "Now it was time for me to take the next step."
Dortmund finished second in the Bundesliga this season behind Bayern Munich after winning the title in the previous two seasons.