A photo of Kendall Jenner laughing while exposing her nipple is "her favourite".
The 20-year-old model is photographed in black and white, pulling down the right side of her black tank top.
Jenner posted the pic to Instagram as a celebration of her 40 million followers.
The snap, taken by sister Kylie is about as carefree as you will see the model, normally the most conservative of the Kardashian clan.
Sister Kim Kardashian previously broke the internet with a racy nude magazine cover for Paper magazine, appearing oiled up, balancing a martini glass on her backside.
More recently she posted a photo of herself completely naked and heavily pregnant on Instagram, in a bid to slam haters who criticised her pregnancy body.