The already packed 53rd Annual Philadelphia Folk Festival lineup is getting four more additions, including singer-songwriter Jason Isbell, who will be a headliner on Sunday night of the festival. A former member of the band Drive-By Truckers, singer-songwriter Isbell has a southern rock, alternative country influenced sound. The festival also added a bonus concert exclusively for All-Festival Camping Ticket holders on Thursday, August 14 — the night before the festival official starts. The concert will be held in the campgrounds and hosted by World Cafe host David Dye. The night will feature bluegrass and country music singer Sturgill Simpson, vintage country songstress Caroline Rose and roots band Parsonfield. For more information about the festival and tickets, go to the Philadelphia Folk Festival website here. Below, listen to Isbell perform “Live Oak” from his Free at Noon concert from August 2013.