Napoli centre-back Raul Albiol insists that people don't "know the true Ronaldo", highlighting his former team-mate's determination to improve as well as his generosity.
Albiol, who represented Los Blancos for four years after sealing a switch from Valencia in 2009, will return to the his former club in February for their Champions League last 16 clash.
And he admits it will be a special occasion for him, having formed a number of strong friendships during his time at the Bernabeu.
"In Napoli the atmosphere is a little more family-like, we enjoy ourselves a lot, although the Madrid dressing room was also great," he told Canale 21.
"I had good Spanish friends, like Ramos and Xabi Alonso, and Cristiano always acted well with me."
When asked to comment on Ronaldo's qualities, he elaborated: "He's a fantastic person; away from football he always tries to help everybody, especially kids.
"He has a part of his personality that many people don't know; people don't know how the real Cristiano is.
"He works a lot to better himself every day, but he's also very generous."
Real welcome Napoli to the Bernabeu on 15 February, before travelling to Stadio San Paolo for the return leg on 7 March.