I Didn't Know About You is a jazz standard composed by Duke Ellington with lyrics by Bob Russell. It began life as an Ellington instrumental recorded in 1942 under the title Sentimental Lady, and the vocal version was recorded in 1944 with Joya Sherrill. A Count Basie & His Orchestra version with Thelma Carpenter reached No. 21 on the Billboard charts in 1945, and other 1945 recordings were by Ellington, Mildred Bailey, Jo Stafford and Lena Horne. Alec Wilder noted that it works well as part of Ellington's series of instrumentals turned into songs with Russell lyrics, the most melodic vocal strain of the three Russell-lyrics Ellington tunes, the others being Do Nothing Till You Hear from Me and Don't Get Around Much Anymore. Notable later recordings include June Christy on The Misty Miss Christy (1956), Ella Fitzgerald on Ella Fitzgerald Sings the Duke Ellington Song Book (1957), Patti Page on In the Land of Hi-Fi (1956), Abbey Lincoln on Abbey Lincoln's Affair... A Story of a Girl in Love (1957), Jo Stafford on Jo + Jazz (1960), and Charlie Rouse with Thelonious Monk on Monk's Straight No Chaser (1966). The tune is a respected 1940s jazz standard and has appeared on several albums, including Ella Fitzgerald Sings the Duke Ellington Song Book.
