Girls Next Door (옆집소녀; Yeopjibsonyeo) was a 7-member project girl group created by the variety show Idol Drama Operation Team. They debuted on July 14, 2017, with their first and only song, "Deep Blue Eyes". The group consisted of MAMAMOO's Moon Byul (문별), Red Velvet's Seulgi (슬기), I.B.I and C.I.V.A's Kim So-hee (김소희), Sonamoo's D.ana (디애나), Oh My Girl's YooA (유아), Lovelyz' Ryu Su Jeong (류수정), and I.O.I and Unnies' Somi (소미).