Watch Serie A live in the United Kingdom on Premier Sports and get your first month free.
The player, who was named the best defender in the Portuguese first tier, Primeira Liga, for five consecutive months, is set to join Madrid by the end of the current season.
Militao has agreed to a six-year deal with Real Madrid.
Militao began his career with home-town club Sao Paulo before moving to Porto during August 2018.
"He comes from Porto, where in his first season he has become one of the main protagonists of the Portuguese League".
Real Madrid entertain struggling Celta Vigo on Saturday on Zidane's return to the Bernabeu and he said he was "emotional to be able to return to the Santiago Bernabeu Stadium".
Atletico Madrid meanwhile must shake off the gloom of their chastening Champions League elimination to Juventus when they visit Athletic Bilbao hoping to keep up their chase of Barcelona, who they trail by seven points.