SBS's "Inkigayo" celebrated their 600th episode earlier tonight, which included a special stage from T-ara. During their "YaYaYa" performance, the girls were to whip out placards spelling out "In-Ki-Ga-Yo", but unfortunately, member Hyomin experienced an embarrassing mishap as she failed to flip over the correct side of the sign. After the show, she took to her Twitter to apologize for the slip-up. She wrote, "When you line it up, it's always the loudest person that gets it wrong... Aigoo... Sorry ??  It's not '600 Kigayo'... "In"kigayo, congratulations ??" Hyomin attached a picture of herself correctly holding the sign, but with a defeated expression. Check out the video below if you missed out on T-ara's "YaYaYa" performance! Source + Photo: Hyomin's Twitter