Kenny Chesney will play an acoustic set at Margaritaville in Key West, Fla., on Wednesday night (Dec. 19). He made the impromptu announcement earlier in the day. The free show will begin at 7:30 p.m. and admission at the 179-seat venue will be offered first-come, first-served. Chesney will be joined by songwriters Keith Gattis ("El Cerrito Place") and Mac McAnally ("Down the Road"). Chesney will launch his 2013 No Shoes Nation tour on March 16 at Raymond James Stadium in Tampa, Fla.