Tony Romo & Jay Cutler better LISTEN UP ... one of the greatest voices in the history of sportscasting is about to give you a foolproof tip on how to kill it behind the mic.
We got Al Michaels out at the Palm in Beverly Hills and asked him if there's one piece of advice he could give to Tony and Jay since both guys are now off the field and in the broadcast booth.
Al -- who's been doing it for NEARLY 50 YEARS -- gives up the secret, and then gives the guys someone to shoot for, telling us who he thinks the greatest analyst of all time is.
Here's a hint ... it's not O.J.