A member of a popular idol group surprised South Korean viewers with her talented vocals on Sunday.

On May 10, f(x)'s vocalist Luna took her mask off on the MBC show Mask King (King of Mask Singer) after losing a round, revealing that she had been the mysterious singer known as Golden Lacquer. Luna had survived several episodes of the show, where she competed against other hidden celebrities.

Luna's unmasking came after weeks where her vocals outstood the in-studio and general audience, while keeping her identity hidden.

Fans of the show and singer offered proof for Luna being Golden Lacquer, but until the unveiling her identity was kept hidden. Even professionals on Mask King were unable to guess the identity of the singers based on her vocals.

During the broadcast and immediately afterward, Luna's name became one of the most searched terms in South Korea. In addition, the term "Golden Lacquer" trended worldwide on Twitter for several hours.

For her final performance, Luna sang the song "Sad Fate."

Fans of Luna expressed excitement that the f(x) singer was gaining well-deserved appreciation for her talent.

"If anyone ever says that f(x)'s main vocalist cannot sing, please guide them [here] to hear," commented noorpreet soni on MBC's official video uploaded to YouTube. "Finally, she gets the attention she has deserved. Even though I'm not Luna-biased, I can say for sure that she is one of the most talented member in f(x). I'm so proud of her!!"

Luna shared a screencapture of the on-air unmasking on her Instagram account.

"Shooting began in March... I'm so happy, thank you," she wrote, with emoticons implying her tears of happiness.

 #복면가왕 #황금락카두통썼네 #에프엑스 #루나 #보컬 #행복 #감사 #일요일 3월부터 시작된 촬영 .. 정말 행복했어요 감사합니다. ㅠㅠ

A photo posted by 박선영 (@fx_luna_sunyoung) on May 10, 2015 at 2:29am PDT