Napoli president Aurelio De Laurentiis has confirmed Allan will join Everton.
The 29-year-old played under Toffees boss Carlo Ancelotti at the San Paolo.
Reports have claimed a £25m has been agreed between the two clubs, which has now been confirmed by De Laurentiis.
He told Radio Kiss Kiss: "We are at the final greetings. Allan will go to Everton."
A Brazil international, Allan made over 150 Serie A appearances in five years with Napoli.
