West Ham have signed Besiktas winger Gokhan Tore on a year's loan with the option of a permanent transfer.The German-born Turkey forward spent two years in Chelsea's youth ranks and played under Hammers boss Slaven Bilic at Besiktas.
He helped his club beat Fenerbahce to last season's Turkish Super Lig title.
The 24-year-old said Bilic was "a big factor" in his move to the Olympic Stadium, adding: "He's the best manager I have played under."
Tore scored four goals and provided six assists in 24 appearances last term as Besiktas won the title by five points.
"He [Bilic] is the main man and knows me very well. I could not have said 'no' to him," said the Cologne-born wide player.
"He is like a father to the players. You feel like you are family."
West Ham said Tore would prepare for the new season at the club's training ground while the rest of the first-team squad finish their pre-season tour of America.