The set up is the classic "confusing a real gorilla for a guy in a suit".
The confusion is only the beginning, the ensuing chase that follows is completely nuts !
Rather than try to describe this lunacy, you can see it right here, all cued up and ready to go.
The guy in the "fake" monkey suit is veteran British comic actor Terry Thomas.
The "director" is played by character actor Vito Scottie.
As for the "Real" gorilla ? here's a few points of interest;
The costume was made by the famous Don Post Studios, makers of the greatest masks ever !
The head of this furry fellow was sculpted by the incredible Marcel Delgado .
If his name doesn't ring a bell, Marcel is the artist who sculpted and fabricated the 1933 King Kong stop motion puppets !
To say Mr. Delgado knows apes in an understatement.
Here is were it gets a little weird....originally, the ape in Perils of Pauline was to be a white gorilla.
As bad luck would have it, it was decided after the suit was finished that they changed their mind and would rather it were a traditional dark gorilla.....The next morning !
Here is the tale as printed in the pages of Famous Monsters of Filmland.
The Delgado gorilla as it's come to be called was used for studio rental suits and appeared in this famous pose with the stunning Raquel Welch as Blonde Venus !