The pair played together for Real Madrid Castilla.
"He encouraged me to come here and had good words to say about Queens Park Rangers," Granero told the Telegraph.
"He's brilliant - wherever he goes he's brilliant. He has the style. When he went from Castilla [Real Madrid reserves] to Valencia he was very young, there were many older players and it looked difficult for him. And he passed over them straight away. He goes to Chelsea - 10 minutes and he scores!
"He's so talented and clever and he's one of my favourite footballers and a good friend of mine. We were in the academy at Real Madrid together, with the national team academy, and now we live in the same city and we've always wanted to do that."