Ronaldo, 36, left Los Blancos in 2018 as he completed a sensational £99.2m move to Juventus.
The Portuguese superstar has enjoyed domestic success with the Old Lady and added two Serie A titles and two Italian Super Cups to his ever-expanding trophy cabinet.
However, Ronaldo is out of contract next summer and his future at Juventus remains uncertain after the defending Italian champions' Champions League exit.
Former Juventus chairman Giovanni Gigli has been critical of Ronaldo as well after he branded the Portugal captain an 'expensive mistake' for the Italian side.
Zidane's first stint as Madrid boss was fruitful with Ronaldo's influence as the pair lifted the La Liga trophy, a Spanish Super Cup and three consecutive Champions League titles.
When asked by reporters about the Ronaldo speculation, the Madrid boss responded: "You know what he is, what he has done and how much love we have for him.
"He made history here, he's magnificent.
"Now, he is a Juve player and I cannot tell you anything about what they [media] are saying. He's a Juve player and I have to respect these things."
The five-time Ballon d'Or winner left Manchester United in 2009 to complete a then-world-record move of £80m to Madrid.
Ronaldo's nine-year stay at the Santiago Bernabeu saw him add 15 trophies to his illustrious playing career, including two La Liga titles and four Champions Leagues.
The former Madrid and United star also became Los Blancos' all-time scorer before he left for Juventus.
Featured Image Credit: PA
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