During her latest concert in St. Paul, Madonna decided to restart her ongoing attack on all things Lady Gaga. It seems Madonna was offended because Lady Gaga rejected her invitation to perform together.
"I have the best fans in the whole world. So take THAT, Lady Gaga! You know, I invited her on stage to sing with me. But, she turned me down. It's okay. I've been rejected before, it builds a little character."