Super Bowl Slack Line Guy Andy Lewis -- Don't Worry, My Nads Are Fine!

We interrupt our usual TMZ coverage for a SPECIAL MESSAGE from the tightrope guy in the Super Bowl halftime show -- "My nuts are fine."

TMZ spoke with Andy Lewis ... the slackline trickster who repeatedly bounced HARD on his crotch during his show-stealing routine -- and he tells us he totally understands why people would be concerned for his man parts.

Lewis -- who has a sponsorship deal with Gibbon Slacklines -- told us, "I've been doing it for years ... and over time your nuts harden to steel."

The daredevil says he doesn't wear a cup ... but notes he's very careful about testicle placement ... "You just try to not squish and pop them ... so you put them to one side."

The more you know.