NU'EST Aron and Len revealed a photo battling their six packs.

On July 11, NU'EST official Twitter posted, "Will it be washing board Aron or chocolate Len? (Six packs)."

In the picture, Aron and Len are showing their six packs proudly and posing for the camera.

Aron has already teased a six pack picture to show his change.

NU'EST released their first official album 'NU'EST The First Album Re:BIRTH' to show their change from boys to men.

NU'EST will make their comeback on KBS Music Bank as well as MBC Music Core to begin their performances.