Caglar Soyuncu, a former Leicester City defender, has signed a four-year contract with Atletico Madrid.
Soyuncu, 27, left Leicester City after they were relegated to the Championship in June, when his contract expired.
After joining Leicester from Freiburg for £19 million in 2018, the centre-back played 132 games, winning the FA Cup and Community Shield in 2021.
Last season, he was frozen out by previous manager Brendan Rodgers.
However, after taking over as interim manager, Dean Smith promptly reinstated him.
Soyuncu missed the final three games of the season due to a hamstring injury, causing Leicester to finish 18th in the Premier League.