MAMAMOO is gearing up for their upcoming best-of album 'I SAY MAMAMOO: THE BEST'.

After the confirmation of the release of their best-of album, MAMAMOO has dropped the first set of concept images for 'I SAY MAMAMOO: THE BEST' on September 5 at midnight KST.

The upcoming compilation album is the girl group's first release since their 11th mini-album 'WAW' released this past June, as well as their first since Whee In decided not to renew her contract with RBW.

'I SAY MAMAMOO: THE BEST' will be released on September 15 at 6 PM KST, so stay tuned for more teasers to come until then.