The Mills Brothers were an American vocal group formed in 1928, known for their smooth harmonies and unique sound. The group originally consisted of four brothers: John, Herbert, Harry, and Donald Mills. They gained popularity in the 1930s and 1940s, recording numerous hits and becoming a staple in the jazz and pop music scenes. Their innovative style included vocal instrumentation, where they mimicked instruments using their voices. The Mills Brothers are best known for songs like "Paper Doll" and "You Always Hurt the One You Love." They left a lasting impact on music and influenced many artists in the years that followed.