On April 4, NCT U was announced with pictures announcing members Mark and Jaehyun, later adding members Taeil, Taeyong, Doyoung, and Ten. NCT U was described as the main group of NCT. It was announced that there will be two NCT U groups, each having different member organization. On April 9, they released the song “The 7th Sense” and "Without You" as digital singles, Jaehyun, Mark, Ten, Taeyong, and Doyoung participated in producing “The 7th Sense” which is described as having a hip-hop groove with a heavy base sound. As for “Without You,” members Taeil, Jaehyun, and Doyoung worked to create the dance EDM song. The group made their debut on music program Music Bank four days later.