What 80s pop singer's nickname is the "Material Girl"?

Material Girl is a song recorded by American singer Madonna for her second studio album, Like a Virgin (1984). After the song's release, the phrase "material girl" became another nickname for Madonna. She often remarked that "Material Girl" is the song she most regrets recording, as it became a label that has been attached to her for decades. She also said if she had known this, she probably would never have recorded it.

Source: Wikipedia