The Material Girl is usually accompanied by a huge entourage and is whisked around in limousines but decided to downplay her celebrity status with a journey into downtown New York on Tuesday.
The 51-year-old singer stood for her train ride and was only accompanied by two men and one woman, Contactmusic reported.
Madonna managed to remain unnoticed until fellow commuters spotted a photographer taking snaps of the star, to whom the unfazed singer said, "I don't mind you taking my photo, but be discreet."