Cheick Doucoure, a midfielder, has been acquired by Crystal Palace in a £21 million deal from French club Lens.
Doucoure has signed a five-year contract at Selhurst Park, pending international clearance.
Palace will pay Lens an initial sum of £18 million, which could increase to £21 million with add-ons.
The Mali international is the third player to join Crystal Palace this summer, following winger Malcolm Ebiowei and goalkeeper Sam Johnstone.
Last season, Doucoure made 34 Ligue 1 appearances for Lens, who finished seventh in France’s top division.
“I’m very happy, I feel a lot of joy and a lot of pride to be a Palace player,” Doucoure told club media. “I’m proud to be at Palace today.”