The At Last Songfacts states that the songwriting team of Mack Gordon and Harry Warren wrote this in 1941 for the film musical Sun Valley Serenade. The following year it was rearranged and re-recorded and used in the film Orchestra Wives. It was performed in both movies by Glenn Miller and his orchestra with vocals by Ray Eberle, and the song became a major big band hit in October 1942.
Etta recorded this in 1961 shortly after signing with Chess records. .