Little Big Town
Little Big Town is an American country music vocal group. Founded in 1998, the group has comprised the same four members since its inception: Karen Fairchild, Kimberly Schlapman, Jimi Westbrook, and Phillip Sweet. The quartet's musical style relies heavily on four-part vocal harmonies, with all four members alternating as lead singers. Westbrook and Sweet also play rhythm guitar.
source: Wikipedia