Pepe, 35, departed from the Turkish outfit last month after only a year at the club since his arrival from LaLiga giants Real Madrid.
The Brazil-born defender was subsequently linked with a host of suitors, including Arsenal and Wolves.
However, former club FC Porto have now confirmed the return of the 109-time capped centre-back, who represented the club between 2004 and 2007 before his lucrative €30m transfer to Los Blancos.
Pepe will provide Dragões with a wealth of experience for the second half of the campaign as the lead second-place Braga by six points in the title race.
The Primeira Liga champions also remain in the UEFA Champions League with a last-16 tie against AS Roma set for February.