Ong Seong-wu is a South Korean singer and actor. He is known for his participation in the survival reality show Produce 101 Season 2, where he finished in fifth place, and is a former member of the show's derivative boy group Wanna One. Following Wanna One's disbandment, Ong made his acting debut with cast At Eighteen (2019). He also established his career as a solo artist with the release of his first extended play, Layers, on March 25, 2020.

Produce 101 Season 2 is a 2017 boy group survival reality show on Mnet, and is the second season of the original South Korean version of the franchise. The public "produces" a boy group by choosing 11 members among 101 trainees from 54 entertainment companies through online voting and live voting with multiple elimination rounds. The public also chose the group's concept, debut song and group name. In the season finale on June 16, 2017, which was broadcast live, the show announced the final 11 members who would debut as Wanna One. More than 16 million people cast their votes during the finale, equivalent to around 30% of South Korea's population.