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In the new preview, the members of Red Velvet shamelessly challenge and poke fun at the cast of 'Knowing Brothers'. Seulgi talks about a mistake she made on stage at their concert in North Korea, Irene perfects her dance moves to "Havana", and Wendy teases Heechul with her brilliant humor! 

Furthermore, Joy's caustic jokes make the cast members ask her if she "recently went through a break-up", and Yeri works up the courage to stand up against Kang Ho Dong. 

Watch the full preview above! Make sure to tune into the next episode with Red Velvet on August 4 at 9 PM KST!