The two players are rivals in La Liga, but Pique has insisted that he 'likes' the Portuguese from their time together in Manchester.
"If I always speak well about Cristiano it's because I like him. People can draw their own conclusions from the gestures and comments, but they don't know. I must add that he's changed a bit recently," Pique told Marca.
"He helped me a lot when I joined United."
Pique played for United between 2004 and 2008, while Ronaldo spent six years at Old Trafford from 2003.