By Brandy McDonnellGrammy Award-winning country music star Carrie Underwood and Tony Award-winning Broadway star Kelli O'Hara have joined the ranks of the Oklahoma-born and bred celebrities using social media to voice their support for the ongoing Oklahoma teacher walkout.Underwood, a Checotah native, comes from a family of teachers, with her mother and older sisters all working in education.Read more on NewsOK.com