to joining SM Entertainment, some of the members were already involved in the entertainment industry. Jeno appeared in various commercials as a child. Jisung was a child actor and filmed movies such as Boys, Be Curious (2012) and Go, Stop, Murder (2013). Chenle was active on the Chinese music scene as a singer from 2009 to 2015; he released three albums and headlined a concert in China. In 2011, Yuta participated in the singing competition "Juice Winter Collection" in Japan, while Ten competed on the Thai TV show Teen Superstar under the name TNT. Xiaojun was a singing contestant on the Zhejiang TV program X-Fire in November 2015. Johnny, Yuta, Ten, Mark and Renjun joined the company via SM Global Auditions, while the remaining members were discovered through street casting, personal recommendation, community entertainment shows, and local auditions. Prior to their debut as members of NCT, 19 of the 23 current members of NCT were introduced as part of SM Rookies, a group of trainees under SM Entertainment created in December 2013. The first members of NCT to be introduced were Taeyong and Jeno. Sixteen other members were introduced through SM Rookies until early January 2016. Taeyong released the short rap track "Open the Door" in July 2014 and featured on Red Velvet's second single "Be Natural" in October of the same year. He appeared alongside Johnny, Yuta, Ten, Jaehyun, Mark, Jeno, Haechan, Jaemin and Jisung on the Mnet-produced Exo 90:2014, a show starring labelmates Exo, where they performed dances to K-pop songs from the 1990s. Some members appeared in various Exo music video remakes in the same year. From January through June 2015, Doyoung and Jaehyun were the hosts of the music show Show Champion; from July through December of that year, Yuta was a Japanese representative on Abnormal Summit, a series in which non-Korean men debate Korean culture. Mark, Jeno, Haechan, Jaemin and Jisung were Mouseketeers on Disney Channel Korea's The Mickey Mouse Club. SM Rookies Boys held their first concert, titled SM Rookies Show, which started in Seoul in September 2015 and expanded to Bangkok, Thailand in February 2016. Taeil released his first solo soundtrack "Because Of You" for the series The Merchant: Gaekju 2015 on January 26, 2016. In April 2016, Kun sang with NCT U on the Chinese version of "Without You" and joined them for the song's promotional stages. Winwin performed NCT U's "The