The Mills Brothers, sometimes billed the Four Mills Brothers, and originally known as the Four Kings of Harmony, were an American jazz and traditional pop vocal quartet who made more than 2,000 recordings that sold more than 50 million copies and garnered at least three dozen gold records.

The Mills Brothers were the first African-American artists to have their own show on national network radio (on CBS in 1930); they made appearances in film; and were the first to have a No. 1 hit on the Billboard singles chart, with "Paper Doll" in 1943. They were inducted into the Vocal Group Hall of Fame in 1998.

Source: Wikipedia (https://en.wikipedia.org/wiki/The_Mills_Brothers)