The aesthetic of ‘cuteness' in South Korean popular music (known as K-pop) is a pivotal concept in Korean media and culture and is frequently used to describe performances by both male and female K-pop groups. Aegyo is a fundamental part of this aesthetic, also called ‘K-cute', and it refers to the behaviour of ‘acting cute' that denotes a particular coquettish style not only in K-pop but also in South Korean society in a broader sense. This thesis explores K-pop performance from the mid-2000s to the 2010s through an examination of K-pop artists' training process, an analysis of K-pop music videos' lyrical and visual codes and a study of notable live performances. The aesthetic of ‘cuteness' in K-pop is contextualised through a historical and cultural review of South Korea and the forms through which aegyo has been represented. Thus, we see how aegyo has evolved in response to gender stereotyping in both traditional and contemporary South Korean society and how it has come to represent a unique idea of Korean-ness expressed in a cultural form that also fulfils its potential for flexibility. Furthermore, this thesis investigates how the K-pop industry influences aegyo through issues of gender and sexuality, primarily examining Richard Schechner's performance theory and Erving Goffman's notion of self-presentation. A significant aspect of this investigation is the sexualisation of K-pop idol boy and girl groups through the deliberate adoption of the aegyo aesthetic, a process that forms a key part of the marketing strategy behind their ‘Korean wave' global success. Finally, I explore mediatised performances of aegyo and the possibility that remediation, as outlined by Bolter and Grusin, provides a potent vehicle for the repetition and reinforcement of ‘cuteness' via holographic and digitalised K-pop performances.