Saba Doru (2012)

Both stories are about a female lead with a secret double identity.

Both dramas focus on lead characters with a hidden identity trying to achieve a career in music.

Both female leads are idols and have a secret identity. In Sabu Doru, the female lead is actually 38 years old. In Mask, the female lead isn't what is considered "pretty" in korean standards.

Teachers with secret identities.
Yankee students.
Life lessons.

Starred by a member(s) of AKB48.
Both include yankees and school life, as well as the clash of 2 very different lifestyles. Both are lively dramas about being who you are, confidence, loyalty, and finding one's path in life/fulfilling dreams.