Jessica Jung has a wealth of experience when it comes to shining onstage as a K-pop star. Rachel Kim? Not so much—yet. Kim, a 17-year-old Korean American vying for the opportunity to debut in a girl group, is the protagonist of Jung’s upcoming novel Shine, out Sept. 29. It’s no coincidence that Rachel’s life mirrors Jung’s—both emigrated from the U.S. to South Korea, both started training to become an idol at the of 11—as the young adult book is inspired by the 31-year-old artist’s life. But Jung says it’s up to the reader to decide the line between fact and fiction. “It’s going to be like an Easter egg hunt,” she tells TIME. “Looking for clues and who’s who, what’s what, what’s true, what’s not.”
Jung and her younger sister Krystal Jung were scouted in 2000 by SM Entertainment, a major label that’s home to some of the biggest K-pop groups. The elder sibling spent seven years as a trainee, the term used to describe aspiring artists in the Korean music scene, before debuting in 2007 in the nine-member group Girls’ Generation. Widely heralded as one of the most influential K-pop acts that helped introduced Korean music to the world, Girls’ Generation became the first K-pop group to reach 100 million views on YouTube in 2013—with the hit song “Gee.” Jung departed from the group in 2014, and has since released music as a soloist, starred in movies and continued building her fashion brand, Blanc & Eclare. With Shine, she makes her literary debut.
The vivid novel focuses on Rachel Kim’s time at the fictional company DB Entertainment, where strict rules like no dating and a zero-tolerance social media policy are enforced. Over Zoom, Jung spoke to TIME about what motivated her to write Shine, how she incorporated personal experiences into the book and who she hopes will be cast as Rachel in the on-screen adaptation—currently being developed by the team behind To All the Boys I’ve Loved Before.
TIME: Why did you decide to write Shine?
Jessica Jung: I was in this industry for 10-plus years; it was my 13th anniversary this year. I started at a very young age, and I had a lot of chances to travel around the world and always thought that I had a story to tell. I had a lot of drama, a lot of competition, boys—everything that I wanted to tell the world about.
Is there a reason you chose to set the book during the pre-debut period, when Rachel is a trainee?
There’s a lot of information out there about what it’s like to be a K-pop star, but not a lot of people know about the behind-the-scenes of what it takes to become a K-pop star, and what you go through to get your chance to debut. I really wanted to share that.
The story is told through Rachel’s perspective. In what ways do you think your voice is similar to Rachel’s, and in what ways is it different?
Rachel is a reflection of me, of course, because this novel is inspired by my own life. But I did try to fictionalize everything. She was born in New York, I was born in San Francisco, for instance. I never wanted to write an autobiography or a tell-all story. I wanted to make good entertainment.
In the book, DB Entertainment has a lot of strict rules for its trainees, like no dating and no social media. “Trainees do not post and are not posted about, ever,” Rachel says. How much of this was based on your experience?
All of them were based on experience. Yes, there’s a lot of rules and there’s a lot of things that people might not understand, but that’s what we had to go through. No phones, no SNS [social networking service, the primary term used to refer to social media in South Korea], no texting—just practice. But that’s why we were able to concentrate and get to where we are.
Have the rules changed over time?
The rules of no dating, no phones, always have to be on a diet, no texting—those all still exist. Talking to my friends in the industry right now, nothing has changed.
You were very young during your years as a trainee. How do you look back at that time of your life and how it shaped you?
Looking back at my trainee years, I am actually very proud of myself. As a young kid, you may want to go out and play with your friends, go out to the movies, do sleep-overs. But I wasn’t able to do that, and it took a lot of self-discipline and patience.
You dedicate the book in part to your sister Krystal, who you write is “the brightest light” in your life. Could you talk about the role she played in your trainee years?
Not just in my trainee years but throughout the years, even up until now, my sister Krystal has been my biggest supporter, and we support each other no matter what. It can be hard to find true friends in the industry. It’s truly a blessing to have a little sister to always talk to and have my back.
Going back to what you said about incorporating your own experiences, could you share if some characters were more based on real people than others?
Leah is definitely a reflection of my little sister, and my sister picked her own name, by the way. She was like, “I want to be Leah.” And I really wanted to portray our relationship in the book accurately, so I hope the readers enjoy that.
I’m sure readers will also be curious if Jason Lee—the DB heartthrob who’s a member of the hottest new group—is based on a real person?
Jason may or may not be based on a real person. But that’s up to the reader’s imagination.
It was all of my childhood, it was—it’s still my life.
Was it a big part of your life before you became a trainee?
Actually, no. Before I was a trainee, I was just a normal kid. I did like K-pop, but I was just a normal kid who went to school, did her homework, had piano classes, went to ballet classes, and I never really imagined myself as K-pop star.
Do you think the general public, whether in Korea or globally, has misconceptions about K-pop idols?
The general public thinks that K-pop idols are perfect—or their choreography is perfect, their vocals are perfect, everything’s perfect. But you know, it all comes from so much effort. I just wish that people would really recognize their efforts and their hard work.
What do you think of how far K-pop has come in the recent years?
BTS, Blackpink—they’re on Billboard, doing a lot of collaborations and being on Western TV, it’s very exciting to see and watch. When I travel the world, people really recognize K-pop and they recognize me, as well. When I debuted in Korea, I thought Korea was my only territory, and [Korean would be] the only language that I’m ever going to speak when I work. But now, you travel all over the world, you meet a lot of different people from different countries.
Throughout the book, you use Korean terms from words referencing family members to names of food. Why did you decide to incorporate Korean language into the text?
I thought it would be fun if people don’t know the word but look it up and learn Korean. Because when I read or see movies with different languages, that’s what I tend to do, and that’s how I get interested and motivated to learn the language. So I hope my readers will learn a little bit of Korean.
Shine is part of a two-book deal. Could you share updates on the sequel or the process of writing it?
We’re developing the second book right now. There’s so much more to Rachel’s journey. I feel Shine ended at just the right time, and then the second book is more into when she’s very successful in life and the things behind-the-scenes of when she’s actually a K-pop star.
There are plans for Shine to be adapted for the screen. What are your hopes for the casting?
It’s just my wish, but I think it would be fun if my little sister, Krystal, actually starred as Rachel because she knows so much about Rachel. I think she would be awesome.
This interview has been edited and condensed for clarity.
—with reporting by Aria Chen