On Sunny’s radio show, Sunny’s FM Date, f(x)’s Luna shared a touching story about f(x)’s tough road prior to their debut.

After choosing to play Kelly Sweet’s “We Are One” she explained, “This is a song I chose for our f(x). It’s a song that warms my heart and makes me cry tears of joy.”

She went on to explain the story behind the song as the group prepared for their showcase, “We had no idea if we would be able to debut tomorrow or a year from then. The members stuck by each other and promised, ‘Let’s do well. Let’s work hard and succeed.’ At the time, we were only 15-16 years old.

We tried to become a source of strength for one another and on days where we fought, got upset, or felt sick we’d stop rehearsing, lay down on the floor together, and play this song.

The beginning of this song reminds me of my mother. It’s a song that helped us unite as one when we were all physically and emotionally drained. When we were laying down together, we’d cry, laugh, and sometimes even fall asleep to it if we wanted to.

One night, we had a 10 hour evening rehearsal. Honestly, at the time I was very hard on the members. I’d write 1 to 100 on a notepad and cross out a number after each practice. Whether it took all night, 10 hours, 5 hours it didn’t matter because I thought it’d be better to count practices rather than to go by time. It was so we wouldn’t get tired. We a goal to work towards. We were so young that we needed something to keep us motivated or we’d stop.

The rehearsals became too much for the members and I understand what they were feeling. I was so focused on me during the rehearsals, I didn’t think of the members. I could’ve been more understanding and let us take breaks but I was greedy and didn’t put the members first. We were all so tired and missing our moms. There was a day where we played the song and cried a lot. I just wanted to debut quickly. I’m sorry about what happened then. When I listened to this song, I remember thinking that I wanted to be with my members until the end; that we could be a source of strength for each other when we are tired. When I listen to this song now, I’m reminded that we are truly one….”

Those who heard the story were touched and after it was posted online, fans rushed to share their sentiments for the hardworking singer.