Zidane's return to the 13-time European champions was confirmed on Monday and the club has wasted no time in rebuilding their squad.
Long-term FC Porto target Éder Militão has been announced as the first signing in the Frenchman's new reign and reports in Spain suggest the club has met the €50 million (R817m) buy-out clause
The 21-year-old central defender is comfortable at right-back and in midfield and has been courted by a host of Europe's elite but Los Blancos have acted swiftly to secure the signature of the highly-rated Brazilian talent.
"Real Madrid CF and FC Porto have agreed the transfer of the player Éder Militão, who will be linked to the club during the next six seasons, until June 30, 2025," read a statement on the club's website.
The Brazil international has played 34 times for UEFA Champions League quarter-finalists this season, scoring three goals and registering two assists across all competitions.