On the May 27 installment of 'Mask King', a contestant under the mask of 'Jewelry Sauna' faced 'Open Air Bath' in the very first round. The two sang Joo Young Hoon's "Our Love Like This". As soon as the panel and the audience heard 'Jewelry Sauna's voice, they were simply mesmerized by the clear, stable voice and how well it fits with 'Open Air Bath's low, deep voice. 

Despite the great performance, however, 'Jewelry Sauna' wasn't able to make it to the second round and revealed her identity to the viewers. Many were shocked to see Kim So Hee under the mask! As she wrapped up her cover of Kim Chung Ha's "Roller Coaster", the panel continued to comment on how pretty her voice is and expressed their disappointment of not being able to hear her sing again in the next round.

Did you know 'Jewelry Sauna' was Kim So Hee?