Lens sporting director Antoine Sibierski has revealed Chelsea are set to sign Thorgan Hazard on Friday.
Hazard is set to follow elder brother Eden, who left Lille earlier this summer, in making the switch to Stamford Bridge.
Sibierski told his club's website on Thursday: "It should be official tomorrow. (When I arrived) there was no intention of letting him go and I met him very quickly after my arrival to show my confidence in him.
"He still had one year left and it was proposed he extended it but he told me eye to eye that did not interest him and he wanted to leave Lens. I realised 48 hours later why, when I learned Chelsea wanted him. I understand."
Lens coach Jean-Luis Garcia offered his best wishes to the attacking midfielder.
"He is a boy of 19," he said. "His elder brother signs for Chelsea and he is urged to do so by the same club, who won the Champions League. Congratulations to Thorgan. Unfortunately we cannot go against such an opportunity. Good luck to him."