Napoli agreed to pay €50 million plus bonuses for the 21-year-old striker, according to The Guardian's Fabrizio Romano. That would constitute a club-record fee, eclipsing the reported €39 million Napoli spent on Gonzalo Higuain in July 2013.
However, a source familiar with the transfer told Agence France-Presse that the deal is worth up to €80 million. That would make Osimhen the most expensive African footballer of all time, alongside another former Lille player, Nicolas Pepe.
Osimhen scored 13 goals in Ligue 1 before the coronavirus pandemic forced the season to be canceled.
He's expected to replace Arkadiusz Milik, who informed Napoli boss Gennaro Gattuso that he'd like a "change of scenery." Milik has been linked with a move to nine-time defending Serie A champions Juventus.
Lille made a significant profit on Osimhen, who arrived last summer from Belgian club RSC Charleroi for a reported €14 million.
Under sporting director Luis Campos, the Ligue 1 side has increased its profit margins dramatically. Lille sold Pepe to Arsenal last summer for a reported €80 million and Rafael Leao to AC Milan for €23 million.