[3] Since their last album Destination in 2010, the only time that Kim got active in music was during his and Heo Young-saeng's Kyu Jong & Young Saeng Story joint fan meeting in Seoul and other countries across Asia.

[4][5] Kim was also featured in Heo's debut solo album Let It Go in the song "Rainy Heart",[6] though he was not seen in the music video.

[8] During this time, Kim had been busy with his Goong musical, a spin-off of the Korean television drama of the same title, at the Kyoto Minami-za, Japan.

[10] On September 22, a 34-second video teaser of his titular single "Yesterday" was released through B2M Entertainment's official YouTube account.

Two days after the release of his mini album, Kim Kyu-jong revealed during an interview that he almost quit the music industry.

Nevertheless, he continued performing after receiving encouragement from his fans and friends, particularly his label-mate and fellow member Heo Young-saeng.

[17] Kim Kyu-jong had his first comeback stage on September 29 on Mnet's M!Countdown, performing his lead single "Yesterday".

"[8] On September 29, two days after the album release, Kim Kyu-jong said that the photos would get the attention of people whether their reactions are positive or negative.

In addition, he said that the reason why he dressed as a woman represents two things: breaking-off from the inside to show his own colors on the outside and; putting one's own image to the person he or she likes.