 Following an unsuccessful debut with the single "Rocket Girl" in August 2011, Stellar underwent a line-up change and released "UFO" in February 2012, which fared similarly.The group began working with production team MonoTree in July 2013 and released "Study", which experienced modest success and became their first single to chart in the top 100 of the "Gaon" Digital Chart.Stellar gained notoriety in February 2014, when they adopted a more "provocative" image for the release of their first extended play "Marionette".