Big & Rich's Big Kenny, Kathy Mattea and Jo Dee Messina appeared at the Stage, a Nashville honky-tonk, on Thursday morning (Feb. 12) to preview the worldwide Earth Hour event. The third annual Earth Hour will take place on March 28 at 8:30 p.m. as businesses and citizens turn off non-essential lights for one hour as an action against climate change. The event is sponsored by the World Wildlife Fund. Other musicians who have pledged to turn off their lights during Earth Hour include Dierks Bentley, Vince Gill, Amy Grant, Lady Antebellum, SHeDAISY and Wynonna. Nashville mayor Karl Dean said all downtown businesses, including CMT and the Lower Broadway honky-tonks, will turn off their lights at the appointed hour in conjunction with numerous cities around the world.