WWE Guest Commentators

   When the WWE has a "guest commentator", (I.E.-some mainstream celebrity or sports star), are they told ahead of time what to say, or is simply all on the fly?  I still remember Art Donavan's commentary at King Of The Ring 1994.  Even though my friends and I were teenagers at the time watching, we all cracked up over how spectacularly awful he was.

​They are very specifically told what to talk about unless they're a giant celebrity like Arnold.​