The Super Eagles forward ended his association with Belgian side RSC Charleroi when he penned a five-year deal at Stade Pierre-Mauroy.
Now, he hopes to make a good impression in France and emulate Nigeria’s celebrated sons - Peter Odemwingie and Vincent Enyeama - in the process.
"Lille is a very good club that has a quality project and includes high-class players, even more in recent years," Osimhen told the club website.
"Great Nigerian players have also played here. I would like to join their lineage and follow their footsteps.
"I am very happy to be here and to join this great club. I am still young, I am learning and I think that this project suits me perfectly to continue to progress."
Osimhen will be hoping to fill the big boots of Nicolas Pepe, who joined Arsenal for a club-record £72million fee.