Listen to Regan's Theme  (From “Exorcist II: The Heretic") online. Regan's Theme  (From “Exorcist II: The Heretic") is an English language song and is sung by The City Of Prague Philharmonic Orchestra. Regan's Theme  (From “Exorcist II: The Heretic"), from the album The Essential Ennio Morricone Film Music Collection, was released in the year 2016. The duration of the song is 2:39. Download English songs online from JioSaavn.