diegolunadaily:

Hi, it’s not true but this rumor isn’t coming out of nowhere because Gael once joked he and Diego

auditioned for Harry Potter: “Well, we auditioned for “El Hobbito.” [laughs] Yeah, the same thing happened when we auditioned for Harry Potter [and the Prisoner of Azkaban, which Alfonso Cuaron directed]. They said, “Uh, we’ll call you.” And they never called us! Basically what happened with Harry Potter is that part of the audition was to fly with a broom, and we did it, but it didn’t look so good because we hadn’t done it in a while. [To Luna] Right?

I mean, we’d done it a few times when we were kids, but not anymore.” 

People have been fancasting Diego as Sirius or/and a young Snape since I remember but Warner Bros. missed the opportunity.