On April 12, 2013, Core Contents Media announced a sub-group called T-ara N4. The members were Jiyeon, Eunjung, Hyomin, and Areum. The group's first song, "Jeon Won Diary", was inspired by a 1980s drama show. It is a "funky and intense" dance song with elements of hip-hop. T-ara N4 released the song, the extended play (EP) of the same name, and a music video on April 29, 2013.