Celebrity Mystery Ass And the Butt Belongs To ...

6/5/2013 8:35 AM PDT BY TMZ STAFF
This smokin' hot celebrity butt was spotted at a pool in L.A. this weekend ... but the question is -- WHOSE ASS IS IT???

Here's a tip ... she used to bang a SUPER famous person ... and then moved on to a not-as-famous person.

Can you crack the case??