Monaco have secured the services of Kamil Glik from Torino in a deal believed to be worth EUR8million.
The centre-back recently revealed he was close to joining the Ligue 1 side and he has now completed his move to the Stade Louis II.
The Poland international has signed a contract with his new club until June 2020, after helping his country to the quarter-finals of Euro 2016, where they were beaten on penalties by Portugal.
"I am very proud and happy to have signed for Monaco," Glik commented on his move.
"Monaco are a big club in France and allow me to take the next step in my career.
"I am going to give my all to help this club reach its objectives. It is a very exciting new challenge and I cannot wait to get started here."
Monaco have already signed Benjamin Mendy, Youssef Ait Bennasser and Miguel Veloso ahead of the new season.