It all went down when Miley was on stage, and was handed a Selena cutout by a fan in the crowd. She sang her song "FU" to the cardboard with Sel's face on it and then tossed it into the audience.
According to Hollywoodlife.com, Selena wasn't happy about the twerker's gesture at all. She pretty much thought it was a diss, and thinks Miley will do anything for attention. Because of that, Selena apparently has "no respect for her." She even feels sorry for her for stooping to such low extremes. Ouch.
This isn't the first beef between Selena and Miley. The two ladies supposedly started feuding awhile back when Selena was dating Bieber. She apparently didn't like his close "friendship" with Miley.
It seems like basically everyone in the young-celeb famous crowd is over hanging with Miley these days. Perhaps she's just too wild and crazy for them? She's supposedly not a fan of Taylor Swift, Demi Lovato, or the Jonas Brothers...
Are you on team Selena or team Miley?