Back in the early 2000s, a few friends and I visited then-MGM Studios while they still had Who Wants to be a Millionaire. The host came out, and my best friend and I kept talking about how he looked so familiar. About 10 minutes in with the first contestant in the hot seat, we both looked at each other at the same time and said "Supermarket Sweep!" Yes, we swear it was the former host of Supermarket Sweep!
After playing along, I actually had the top audience score and was the second person in the hot seat. I just remember being in awe.
I don't know if he was just there for a limited time, and I've done Internet searches over the years to try to confirm this, but found nothing. But we swear it was him...