John Trehy is a film producer. He worked as a financial controller on the film adaptation of Harry Potter and the Philosopher's Stone, a production controller on the film adaptation of Harry Potter and the Chamber of Secrets and the film adaptation of Harry Potter and the Prisoner of Azkaban, and collaborated with David Heyman from the film adaptation of Harry Potter and the Prisoner of Azkaban to Harry Potter and the Deathly Hallows: Part 2
He also made a cameo appearances as one of the Healers in Portrait in the film adaptation of Harry Potter and the Prisoner of Azkaban and the film adaptation of Harry Potter and the Order of the Phoenix[1].
