Connie Britton has been cast in the lead role for ABC pilot “Nashville,” written by Callie Khouri and R.J. Cutler.Britton, who migrated from her Emmy-nominated role on “Friday Night Lights” to FX’s “American Horror Story” last year, will play a country singer whose career is in jeopardy. Hayden Panettiere (“Heroes”) was cast last week as a singing star on the rise. The ensemble for “Nashville” also includes Powers Boothe, Clare Bowen, Eric Close, Sam Palladio, Jonathan Jackson and Robert Wisdom. ABC Studios and Lionsgate are producing. Steve Buchanan will also exec produce.