Lady Gaga at the Much Music Video Awards show in Toronto. (WENN.com)

Lady Gaga has shocked fans by posting a picture online which shows her stripped to her bra and sporting green armpit hair.

The pop superstar has set up her own style blog in recent weeks called Amen Fashion, which documents her wacky outfits and photoshoots.

One picture in particular is causing a stir with fans - the shot shows Gaga reclining on a toilet wearing a green wig, black bra and slashed denim shorts, and one arm is stretched above her head to reveal a shocking green patch of hair.

The picture is titled 'Private In Public'.