For many Brown Eyed Girls fans, Son Gain is the picture of beauty. But when it comes to the way the 26-year-old singer sees herself, it is a different story entirely.

At a press conference on Thursday at the Mega Box Theatre in Seoul for her upcoming film "The Huntresses," Gain admitted to having feelings of inadequacy after seeing the toned physiques of her co-star Ha Ji Won.

"Ha Ji Won has amazing abs," Gain told eNEWS.

"I was embarrassed to have my fat stick out from the sides. We all had the same size for belly dance outfits, but it was only tight for [my co-star] Kang Yea Won, so I got little jealous."

Gain enjoyed the process of making "The Huntresses," but refused to speculate how it will do with audiences.

"I had fun filming," said the Brown Eyed Girls singer. "I had fun watching it, but I don't know what the audiences will think."

A version of Alexandre Dumas's 1844 novel "The Three Musketeers" reimagined during Korea's Joseon Dynasty, the plot of "The Huntresses" focuses on "three beautiful musketeers fighting against a powerful group who tries to overturn the royal family and gain absolute power," according to the reference website AsianWiki.

"The leader of the Beautiful Three Musketeers is Jin-Ok [played by Ha Ji Won], a smart and righteous woman. Hong-Dan [played by Gang Ye-Won] is the only married woman among the three women."

Gain's character is described as the youngest among the musketeers who "excels at fighting."

"The Huntresses" opens on Wednesday.

Gain made her professional acting debut back in 2010 on the South Korean daily sitcom "All My Love."