The Sao Paulo midfielder has joined the Castilla in an initial loan agreement.
"Sao Paulo is a fantastic team, one of the world's best.
"I decide to leave for Real Madrid because it is the one club I'd leave for. It's a great opportunity. When I learned that Madrid was interested in me and that my contract was endorsed by Jose Mourinho I did not think twice.
"This is the reason why I decided to leave Sao Paulo, it was Madrid who knocked."