グレイテスト・アイドル (Greatest Idol) is an album by Mitchie M, primarily featuring Hatsune Miku (although the vocals of Megurine Luka, the Kagamines, MEIKO and KAITO are also featured). It includes all the songs from Mitchie M's previous album and several new tracks.
In addition to the regular version of the album, there is also a limited edition, which is planned to include a "limited deluxe LP (12 inches) package and booklet". Both have a DVD included.
The album debuted at 4th on the Oricon charts.