The "Roma" director spent time at the Telluride Film Festival looking back at arriving in Hollywood with "Harry Potter and the Prisoner of Azkaban."

Alfonso Cuarón was hot off the international success of “Y Tu Mamá También” when he signed on to direct “Harry Potter and the Prisoner of Azkaban.” The decision not only gave the filmmaker his first major Hollywood production, but it also earned him pull in the industry and set him up to director bigger-budget fare like “Children of Men.” During his trip to Telluride this year with new drama “Roma,” Cuarón remembered how he originally wasn’t going to take the offer to direct “Harry Potter” and that it was Guillermo del Toro who convinced him to think otherwise.

“I talked with Guillermo, as I always do, and he says, ‘What’s happening? Any projects going on?'” Cuarón said about his career following “Y Tu Mamá También” (via Vanity Fair). “I said, ‘I’m going for ‘Harry Potter,’ can you believe it? And I even made fun of it. I hadn’t read the books or seen the films. And then he looks upset with me. He called me flaco, that means skinny [in English].”

Del Toro then launched into a explicative-filled rant in order to convince Cuarón not to underestimate “Potter” just because it was a hugely popular film and book series. “He says, ‘Fuckin’ skinny, you’re such a fuckin’ arrogant bastard. You are going right now to the fuckin’ bookshop and get the books and you’re going to read them and you call me right away,'” Cuarón said. “When he talks to you like that, well, you have to go to the bookshop.”

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Cuarón immediately began reading J.K. Rowling’s books following his conversation with del Toro. The director said he was midway through “Prisoner of Azkaban” when it dawned on him this was a serious opportunity he couldn’t pass up.

“I called [del Toro] and said, ‘Well the material’s really great,'” Cuarón said. “He says, “Well, you see you fuckin’…,’ I mean, it’s just untranslatable from the Spanish. As a filmmaker, it was almost like a lesson of humility, of saying how am I going to do it my own, but at the same time, respecting what has been beloved in those couple of movies.”

Cuarón earned acclaim for “Prisoner Azkaban,” which is often regarded by critics as the best entry in the “Harry Potter” film franchise. The filmmaker returns to theaters this December with his Netflix original “Roma.”

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