Many of the dance scenes were shot in single takes and at wide angles to show that the dancers were really doing all the steps.
The credit "improvography by Gregory Hines" means that he made up many of his own steps rather than sticking to choreographed moves.
Harold Nicholas and his older brother, Fayard, were The Nicholas Brothers. They can still be seen in old musicals dancing their amazing acrobatic tap.
The singer at the Times Square club was the great Etta James.
This was to be Sammy Davis, Jr.'s last appearance in a theatrical motion picture. He appeared in two made-for-TV movies before his passing in 1990.