Once again, YouTube serendipity lead me to this:
Written, directed by and starring Anthony Newley as Merkin with his wife,Joan Collins("Polyester Poontang"), Milton Berle("Goodtime Eddie Filth") and George Jessel("The Presence")! This little mindrocker is a mid-life crisis musical mockumentary with a not-too-subtle dash of Fellini whimsy. Here's the trailer:
Another scene with George Jessel and Milton Berle!
According to a commenter on IMDb, Joan Collins soon left him after the premiere! Now that is a scathing review!