Girl group SISTAR showed off their increased sexiness.

On August 28, Mnet 'M! Countdown' posted on their Twitter, "What kind of bodies are these. SISTAR who dominated this summer, comeback with a new song. Your one and only chance to please both your eyes and your ears. First comeback stage on 'M! Countdown'. 'I Swear'. Tonight 6PM" along with a picture.

In the picture, the members of SISTAR were all wearing all-black outfits, from shorts to see-through look and net stockings.

Internet users who saw this commented, "Wow, I'm excited," "The song is so good," etc.