Well, a few years before she got famous, her ass wasnt "as" big as it is now. It could be just a normal thing like some women get huge asses while everything else is normal. But it could also be from surgery, which i higly doubt when u look at her cellulite.

It might be not as beautiful as her face/tits (on which she actually had surgery on) whatever, but for asslovers, this is the dream