On the March 16 episode of 'I Can See Your Voice 5,' MAMAMOO were guests on the show, and their task was to guess which of the mystery singers were lip-synching.

When one of the MCs asked the group if they'd ever lip-synched before, MAMAMOO replied, "Yes, we have, just once. But we failed." 

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The girls explained that lip-synching was difficult for them, since they almost never do it. "It is not something we do often, so our mouths and microphones were all moving at a different pace," said the members.