The original "Three O'clock Blues" was recorded by Lowell Fulson with his brother Martin in 1946. The single was released two years later and established his career.

The same tune probably launched another career when B. B. King topped the R&B chart in 1951 when he recorded "3 O'clock Blues" in the Memphis Y.M.C.A. the year prior and includes Ike Turner on piano. If you've seen B.B. in concert then he must have played this. Wikipedia: ""3 O'clock Blues" launched B.B. King's career and gave him his first opportunity to perform in front of national audience. Due to the song's success, he began performing in the big theaters, such as the Howard Theater in Washington and the Apollo in New York, with a significant increase in his weekly earnings, from about $85 to $2,500. It sparked a touring schedule that continued throughout King's career. In 1956, the song was included on King's first album, Singin' the Blues. It has remained in King's repertoire and he has recorded several versions of the song, including a 2000 release with Eric Clapton for their Riding with the King album."