SEE ALSO: Hyosung speaks about promoting at the same time as G.NA and Jiyeon with songs all by the same composer

Duble Sidekick's Park Jang Geun shared, "The release dates of their albums were initially all different... It overlapped with the Sewol tragedy, so it inevitably became a sorry situation..."

He explained why they went with a more cute concept for G.NA's "Pretty Lingerie" ("G.NA's Secret"), "It's been a long time since G.NA dated, so she wants to find love."

For Hyosung however, he revealed that "sexy" was the keyword, "The lyrics, 'Your goodnight kiss is so sweet. Sleep tight my baby,' in the title track 'Good-night Kiss' comes from the American lullaby, but since Hyosung is singing it, it sounds very sexy."

Duble Sidekick also explained that as T-ara and Jiyeon have been through a lot, he tried to express that through a song about a woman who gets hurt from love and experiences loneliness and sorrow in "Never Ever" ("1MIN 1SEC"), making her maturity the focal point.

Jiyeon will be making her solo debut with "Never Ever" ("1MIN 1SEC") on May 20!