In July 2010, Girl's Day debuted with five members: Jihae, Jisun, Jiin, Sojin, and Minah. The first song by Girl's Day, "Tilt My Head" ("갸우뚱"), was released July 7. Their debut EP Girl's Day Party #1 was released two days after this release. The group followed up promotions for "Tilt My Head" with the song "How About Me" ("나어때"), for which they released a music video on July 21. Two months after the group debuted, members Jisun and Jiin left the group to pursue individual interests. Current members Yura and Hyeri were then added to the group to replace them. The new lineup's digital release Girl's Day Party #2 became available on October 29. The song "Nothing Lasts Forever" ("잘해줘봐야") was used as the lead track of the digital single.