Justin Bieber was grossed out by a female fan getting all up in his space for a pic, and he let her know it ... straight up.
Justin was in Melbourne, Australia Saturday, where a young girl tried snapping a selfie of herself next to the pop star as he grubbed on some finger food. He lectures her on respect ... and then burns her with a harsh line.
Bieber ... don't bother him ... he's eating.[TMZ]
