The "Poker Face" singer - whose original moniker is Stefani Joanne Angelina Germanotta - was given her stage name by her manager when she was 19 and that is the only name she will respond to.
The 23-year-old star said: "Lady Gaga was a nickname given to me by my manager and it's stuck."
"I started using it properly when I was 19 as I was fed up with people yelling about 800 names at my every day."
"So I just told everyone call me Gaga, it makes it much easier as that way I know who everyone is talking to."
The blonde star - who is famed for her outrageous fashion sense - also revealed classical music inspired her to pursue a chart career.
The "Just Dance" hitmaker says classical songs are very similar to the layout of pop tunes and wanted to pen hits after hearing the work of German composer Johann Sebastian Bach.
She said: "Pop music is very similar to classical music. If you listen to Bach you'll hear all his tunes go the same way as a pop record."
