Ivorian forward Salomon Kalou has signed a four-year deal with Lille after passing a medical on Saturday, the Ligue 1 club announced on its website.
Out of contract following his release from Chelsea, the 26-year-old reportedly agreed terms with the club at the end of June.
"The LOSC (Lille) project, in particular the arrival of the new stadium, is ambitious and really pleased me," Kalou said.
"From what I've already discovered about the club, it has no reason to envy the big European teams. I am here to have fun and to get to know the fans who I know are very warm."
Kalou is expected to serve as a replacement for departed Belgian star Eden Hazard, who moved in the opposite direction at the start of the summer. Kalou joined Chelsea from Dutch outfit Feyenoord in May 2006 and scored 60 goals in six seasons for the Blues.