Why does he call me another name other than my real name?

my friend isn't attracted to me but we have hooked up a lot calls me kristin and says i am like kristin cavalerri from laguna beach and i think he tells his friends my name is kristin,why do you think he call me kristin when thats not my name?he says your government name is ##### and your street name is kristin,now whats this all about ,any ideas i am clueless if you don't know just guess ok