Oh Jun Ho, known professionally as O3ohn (pronounced Ozone), is a South Korean singer-songwriter. He graduated from Gwacheon High School and he chose his stage name as it was his childhood nickname and O3 is the chemical formula for Ozone. After being discharged from his mandatory military service around 2015, he became the guitarist of his childhood friend Shin Se Ha's band called "Shin Se Ha and the Town". He later debuted as a soloist releasing his 1st EP "(O)" in 2016. He then appeared in some episodes on "Yoo Hee Yeol's Sketchbook" between 2018 and 2019 promoting his music. In 2020, he entered the singing survival show "Folk Us" and surprised the judges with his vocals and managed to earn 3rd place. In 2021, he began streaming his music online and he has also provided some OSTs for dramas such as "Jirisan", "Link", and more recently "Extraordinary Attorney Woo". (Source: Korean = Namu Wiki) Watch drama online for free.