Four players will move in the opposite direction as part of the deal, goalkeeper Orestis Karnezis, plus youth team players Claudio Manzi, Ciro Palmieri and Luigi Liguori.
“We are very happy at Osimhen's arrival," said De Laurentiis on Radio Kiss Kiss.
“The young man has been enchanted by Partenope (the ancient name for Naples). He will wear the Number 9 jersey."
This is only a taster of the full radio interview, which will be transmitted this evening, but the radio station did release some key quotes, including the debate over how much the transfer cost.
“Gattuso really wanted to sign Osimhen. (Director of sport Cristiano) Giuntoli did a great job, because the lad changed his agents during the negotiations.
“Lille will receive circa €80m, while the player over the years will get between €4m and €4.5m per season."