First time director Lee Seong-tae is making a big splash in the Busan Film Festival’s Korean Cinema Today section thanks to his own reputation and his casting of two hip names.

After short film “The Ten Minute Break,” which traveled to multiple film festivals and won awards, Lee took nine years to make his feature breakthrough. Yet his “Derailed” was the first BIFF film to sell out tickets for Sohyang Theater.

The crime action stars blockbuster character actor Don Lee (“Train to Busan”) and Choi Min-ho (“Canola”) from top K-pop band SHINee.

“I am a new director, and ‘Derailed’ is an indie film with little commercial potential. The script was turned down by all the investors we had pitched to. It was after (Don) Lee and Choi had confirmed their participation that the film’s IPTV rights were pre-sold,” Lee told Variety. “The rest of the less than $500,000 funding came from the film’s executive producer Kim Young-min.

The film tells the story of a teenage runaway who tries to rescue his girlfriend who is forced to work at a sleazy karaoke joint where underage girls illegally serve as prostitutes.

Managed by Korea’s top talent agency SM Entertainment, Choi admits that, as an idol singer at the forefront of the mainstream music scene, it was a new experience to be in a rough indie production.

“Because this character is quite the opposite of the image that I have built up as an idol artist, I thought my agency would oppose my appearance in ‘Derailed’,” Choi told Variety. “When I was younger, I had no real insight about films and acting, and SM chose which roles to go for. But now in my 9th year in the industry, I can raise my voice more and I really didn’t want to see other actors my age play this role.”

“I am an artist after all. Of course it takes double effort if you want to be both a singer and an actor, but you also get double inspiration in return,” Choi said.

Waiting for “Derailed” to open in cinema in November, Lee says he will continue making dark films about troubled individuals.

“I am grateful that this small film, thanks to (Don) Lee and Choi, premiered in Busan. Its screenings and sales have done very well,” said Lee. “I hope the three of us can get together for a new film someday, though not for my next film, because it’ll be about people in their thirties and forties.”