Shōnen Hollywood is a novel writen by Ikuyo Hashiguchi. It was published by Shogakukan in 2012.
32-year old Kōji Sakuragi sees an ad that is scouting for young male singers to be a part of a new group named Shōnen Hollywood. Having once dreamed of being an idol himself, Kōji changes his name to Tsuyoto Hiiragi and lies about being seventeen in order to get in and study at a well-know theatre in Shinjuku called Hollywood Tokyo, where the group will grow and develop their talents.
(The anime takes place 15 years after the events of the novel),