Zac Brown promised fans that he would give an above average show when he came to Charlotte and boy did he deliver on that promise. Saturday night at PNC, Zac Brown brought out a very special guest. A young lady, Brianna Shirley, stepped out on stage and blew the crowd away as she sang, "Colder Weather." According to Brianna's grandmother, she was born legally blind and autistic and she's a huge ZBB fan. Brianna literally stole the show with her performance, this young lady is amazing!!!