By Brandy McDonnellSeveral of country music's top women stars will unite for what's being billed as a "historic, not-to-be-missed" opening performance for next week's 53rd Annual CMA Awards. The Country Music Association announced today that the groundbreaking number led by Checotah native Carrie Underwood, Chockie native Reba McEntire and Dolly Parton will also feature Terri Clark, Sara Evans, Crystal Gayle, The Highwomen (comprised of Brandi Carlile, Natalie Hemby, Maren Morris and Amanda Shires), Martina McBride, Jennifer Nettles, Tanya Tucker and Gretchen Wilson, each performing iconic country songs for a monumental decades-spanning medley never before seen, according to a news release.