C21 is a Danish boy band. It originally consisted of Søren Bregendal, Esben Duus, and David Pepke. The group was formed after producer Lars Quang discovered Søren Bregendal singing and encouraged him to record, later bringing in Esben Duus and David Pepke to complete the trio. Their debut single “Stuck in My Heart,” released in 2002, became their breakthrough hit, particularly gaining traction in Southeast Asia. Their self-titled debut album followed that same year and became one of the most successful Danish boy band debut albums at the time. Their second album, Listen (2004), produced the single “All That I Want,” which reached number 6 on the Danish charts. C21 disbanded during work on a third album in 2005, but they briefly reunited for a live performance in 2014. They officially reformed in 2023 with Søren Bregendal and David Pepke.