On July 2015, UP10TION made its official debut by introducing each member, one by one, through their show Masked Rookie King, also known as King of Masked Rookie UP10TION, which is a parody of MBC’s King of Mask Singer. The members competed and showed their abilities and charms while wearing a mask in front of a panel of judges. Those that were selected took off their masks. The panel of judges were Shinhwa’s Andy, Teen Top’s Chunji, and 100%’s Rokhyun and Chanyong. The first member that was introduced was Wooshin and he was described as a look-alike of the actor Park Bo-Gum. The second and third members were Jinhoo and Hwanhee. The fourth member was Bit-to with a deep soulful voice and the fifth was Kogyeol with a powerful and emotional vocal. The sixth and seventh members were Kuhn and Sunyoul, who both have charming looks and voices. The ten-member group was finally introduced with its latest members Wei, Gyujin, and Xiao.