Eddie Murphy as the straight man? Oddly enough he wrote the story for John Landis’ film and cast himself as a goody-goody who speaks perfectly stilted English, instead of standard scatological Murphy-ese.
In this reactive role, he is an African prince who comes to America pretending to be poor because he’s seeking a bride who will love him for himself alone.
He gives dozens of Paul Hogan-ish deadpan looks and allows his lackey Arsenio Hall and other characters to get the laughs.
Many of these other characters are, in fact, Murphy himself playing cameos (e.g. three-quarters of a barbershop quartet of gabbling fools).
Prince Akeem/Clarence/Randy Watson/Saul
Semmi/Extremely Ugly Girl/Morris/Reverend Brown
King Jaffe Joffer
James Earl Jones