"John Silver" was composed by Jimmy Dorsey and Ray Krise in 1938 and released as a Decca 78 single that year. The instrumental also was released as a V-Disc, No. 117, and was also re-arranged under the title "Long John SIlver" and released as V-Disc 409. It is a Swing jazz classic. Due to the strike in 1942, no new recordings could be made in the U.S. So Jimmy Dorsey, like other bands, performed in movies.
This is from LOST IN A HAREM, with Abbott and Costello. The Jimmy Dorsey band has been hypnotized by the the wicked prince, are in captivity somewhere in Arabia.