The former Real Madrid player and Portuguese international has returned to "Do Dragao" after being released by Besiktas.
Former Real Madrid defender Pepe has re-joined FC Porto after his spell playing for Besiktas after both sides reached an agreement.
Pepe joins Iker at Porto
The deal sees the international move to the current league leaders for the remainder of the current season and the forthcoming campaign, the 'DO Dragao' outfit officially confirmed the acquisition on Tuesday.
His return to Portugal sees the 35-year-old defender reunited with goalkeeper Iker Casillas with both players having played for Real Madrid from 2007 through to 2015.
Following Monday night's 3-1 win over Nacional, the northern based side open a six-point lead over second placed SC Braga at the top of the Liga NoS table.