HyunA will be lending her voice to Indonesian group 'S4' for their debut album.

'S4' was the winner of the first Korea-Indonesian audition project 'Galaxy Superstar Season 1'. They receiving their training from the Korean agency 'Rainbow Bridge' for nine months, and will have their first debut stage in Jakarta titled 'Volume Up Party'.

HyunA was the featured rapper in S4's title song "She is My Girl", a song with a strong beat and addictive melody made by producer�Kim Do Hoon. 4minute will also be participating in their debut stage.