Former FIESTAR member Cao Lu spilled a tiny secret about live singing by idols. 

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On the June 2nd installment of 'Immortal Song', Cao Lu featured as a guest and expressed she was excited for her solo performance on the show. She said, "I was on a lot of variety shows, so I really wanted to sing. I'm thankful for getting the chance to sing. It's been a while since I'm singing live."

The MC panel mentioned she was a part of FIESTAR, but she responded, "When I promoted as an idol, we did sing, but because we also danced, 70% of it was pre-recorded vocals. I'm nervous because today, it's really pure live vocals."

Are you surprised by Cao Lu's admission or were you already aware?