Dr. John came across as a provocateur and a jokester, but his love for composition was serious and straightforward. His affection for Duke Ellington's music resulted in a 1989 cover of “In a Sentimental Mood,” which blends sophisticated strings and acoustic piano. A full tribute album, Duke Elegant, followed in 2000, containing funked-up yet reverent takes of tracks like “It Don't Mean a Thing (If It Ain't Got That Swing).”