The ladies of the nation's girl group Girls' Generation revealed a teaser video for a surprise comeback during their 'SMTOWN WEEK' solo concert, 'Marchen Fantasy'!

Following their encore stage of 'I Got a Boy', the girls announced that they had a special surprise waiting for the crowd that filled the stadium. As the lights dimmed and the attendees held their breath, they were treated to a video teaser showcasing all of the girls with a new black and powerful concept.

The teaser video sent the stadium into an uproar, setting fans ablaze for a long-awaited Korean comeback from Girls' Generation!

Check out the teaser below.

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[thanks to everyone who sent this in.]