The usually well-spoken actress dropped an MF bomb on co-star Robert Pattinson, then went on to slag off reality shows and stars who make sex tapes and take nude snaps.
Teasing co-star R-Pattz from the stage, Reese quipped, "I played your mother, then we had a sex scene, so really you're the best motherf---er in Hollywood."
Moving onto the ladies, Reese preached, "I just want to say to all the girls out there, I know it's cool to be bad, I get it. But it's also possible to make it in Hollywood without a reality show!"
"When I came up in this business, if you had a sex tape, you were embarrassed and you hid it under your bed. And if you take naked pictures of yourself with your cell phone, you hide your face!"
"It's possible to be a good girl. I'm gonna try to make it cool!"
After speculation that Reese's gaff was a reference to Blake Lively's recent nude pic scandal, today her rep told E! News, "Reese was absolutely not referencing Blake Lively."
MovieFIX: More pics and gossip from the 2011 MTV Movie Awards