Paris Hilton has apologized to Kim Kardashian after insulting her former best friend's most famous asset. "I would not want [Kim's butt] - it's gross!" Paris told a Las Vegas radio show on April 14. "It reminds me of cottage cheese inside a big trash bag." However, after a portion of the Kim-bashing interview was posted on perezhilton.com, a devastated Paris realized she went too far. "I was just joking around and I made a stupid joke," Paris tells In Touch exclusively. "I felt really bad afterward, so I contacted Kim and apologized. It was a silly thing to say. Kim's hot!" Kim accepts the apology, telling In Touch, "Paris and I have been friends since we were kids and I'm glad she made the effort to say she's sorry."