MAMAMOO previously unveiled the full tracklist followed by the highlight medley for the upcoming best-of album, 'I Say MAMAMOO: The Best.'

The girl group prepared various remix songs of their hit songs. From orchestra versions of hits like "Paint Me" and "Starry Night," to 2021 editions of MAMAMOO signatures such as "You're the Best," "Words Don't Come Easy," and "Decalcomanie," not to mention some very curious numbers like the 'Blistering sun' version of "Egotistic" or the 'Dramatic' version of "Wind Flower," the upcoming 'Best' album is sure to hit fans with irresistible nostalgia.

On September 10 at midnight KST, MAMAMOO released a special video teasing "Don't Be Happy 2021" in the WAW concert ver. Take a listen to the preview above and stay tuned for 'I Say MAMAMOO: The Best,' coming on September 15 at 6 PM KST!