Are you sure this isn't an official comeback for MAMAMOO? Because that's how good their OST "Girl Crush" for the mobile game 'Innisia Nest' is!

As the promotional models for the game, the girls of MAMAMOO gave their best for their OST "Girl Crush". It's an upbeat and addictive track you'll find yourself nodding your head to, with lyrics pretty much about being awesome and loving yourself.

The song is actually doing amazing on real-time music charts, at least in the top 15 on all main eight charts, and even hit first on Mnet and Monkey3! That's right, their OST for a mobile game is charting higher than a lot of official music releases from popular artists!

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Go click on the OST above to see what the fuss is about!