Senegal captain Cheikhou Kouyate has left West Ham for English Premier League rival Crystal Palace.
"I'm so happy," the 28-year-old midfielder said on Wednesday after signing a four-year deal. "I'm very excited to start with my new teammates.
"This is the right time to move because I needed a new challenge. I have good memories of West Ham but I need to come here and give my best because I like the Crystal Palace project."
No transfer fee was disclosed by the clubs.