Girl's Day (걸스데이) is a four-member girl group formed by DreamT Entertainment in 2010. They debuted on July 9, 2010 with the mini album Girl's Day Party #1.
On February 14, 2017, DreamT Entertainment revealed the plan for the group's comeback, stated the group are focusing on recording.[1] On March 2, 2017, the agency told news outlets that the group are in the process of wrapping up the recording for their title track and the comeback was set on late March.[2] On March 10, the agency confirmed that the group's mini album was set to be released on March 27.[3] On March 17, DreamT Entertainment, released the promotion schedule for Girl's Day's fifth mini-album Everyday #5.[4] On March 22 and 23, four MV teasers showcasing each of the group members for the title track "I'll Be Yours" was released. On March 27, the album and music video for "I'll Be Yours" was released.