Fernando Carrillo attended James' signing ceremony at the Santiago Bernabeu last week.
He told Marca: "He was very enthusiastic more than anything else, very open and very happy. I didn't see him as being at all nervous despite it being a crucial day for his life and for Colombian football. His dream was coming true.
"I think that James has got to where he is because of hard work and thanks to the approach to life that we have in Colombia. We've had a run of recent sporting successes, and the performance that James put on at the World Cup was the cherry on the icing, the result of a lot of hard work."
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