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During the show, Girls' Generation sneakily performed their double title tracks for the cast of the show without them knowing. The group tricked the members of the show by stating that they would be performing a hit song medley. But instead, they started right away with "All Night" which confused the cast of the show and started wondering when and where they've heard it before. By the time they realized the girls were promoting their new songs, it was too late as they finished the performances.

Afterward, the cast of the show confronted Girl's Generation for their trickery but eventually started to get into the dance moves themselves. Check out the hilarious clip above!

How did you like Girls' Generation's episode of 'Knowing Brothers' this week?