This page about British Light Music Composers mentions a song called IF I WERE THE MAN IN THE MOON, by Howard Fisher. I wasn't able to find any further information about it.

AMG - All Music Guide lists 69 recordings of at least 40 different songs called "Man in the Moon."

I don't think I can help you without more information. Do you have any idea who might have recorded it? How old it is? What style it is...blues, calypso, bluegrass...