SEOUL (Korea Herald) - Former Wonder Girls member Sunmi, who rattled the K-pop scene with her viral hit Gashina last summer, returns to that song's world with her new single Heroine.

The new single, released Thursday (Jan 18), is produced by renowned producer team The Black Label. Heroine is a prequel to Gashina, in which Sunmi played a heartbroken woman who blew the ultimate kiss-off to an undeserving lover with a "finger gun".

Heroine flashes back to the past and charts how the protagonist of Gashina became so cynical about love.

During a press conference in Seoul on Thursday, the singer revealed that it was her idea to tell the backstory of Gashina through the new single.

"Some might have expected Heroine would be about me bragging about myself, but it's actually about the man the woman loved," she said. "The woman may appear sad, but as the song's lyric 'the show must go on' shows, she has this 'let it be' attitude."

Retro-tinged Heroine veers away from her electronic-flavored hit, having a more toned-down beat and melodies.

"I'm deeply surprised and grateful for all the love Gashina has been receiving. To tell the truth, I didn't expect the wave would continue to this point," said Sunmi.

She added: "Heroine may lack impact compared to Gashina, but I didn't want to revisit that Gashina route. I wanted to showcase new sides of me."

The singer also said that she has been working on a new project with The Black Label, with plans to continue the cooperation with the team.

Sunmi has been on a winning streak since her first solo outing with tango-disco 24 Hours in 2014. Yet she said she still feels nervous with each new release, especially while waiting for her new song's ranking on local charts.

"Even at this moment, I feel very nervous. I've been in this industry for the last 12 years, but I still can't get used to that anxious moment of watching where my new song lands on charts," she said.

Sunmi debuted as a member of Wonder Girls in 2007 and released her first solo EP Full Moon in 2014. She left the group in 2010, rejoined in 2015, but the group disbanded in January last year following Sunmi and Yeeun's decision not to renew their contracts with the agency.

After leaving JYP, Sunmi signed with MakeUs Entertainment, home to K-pop acts like Park Won and Urban Zakapa, around the end of February last year.