Listen to Hey! It's a Happy Day! online. Hey! It's a Happy Day! is an English language song and is sung by A Very Merry Unauthorized Children's Scientology Pageant Original Cast. Hey! It's a Happy Day!, from the album A Very Merry Unauthorized Children's Scientology Pageant (Original Cast Recording), was released in the year 2005. The duration of the song is 4:37. Download English songs online from JioSaavn.