William Shatner didn’t put anyone in harm’s way while crunching on a bowl of cereal behind the wheel … ’cause as it turns out, the whole thing was part of a bran-new Super Bowl commercial.

The “Star Trek” legend tells TMZ … he’s starring in an upcoming Kellogg’s Super Bowl ad, and during the two-day shoot, there was a moment when a photographer asked him to take some publicity stills in a few different locations.

At one point, the photog suggested Shatner pose behind the wheel while eating a bowl of flakes … and Shatner says he thought it was one of the silliest photos he’s ever taken.

Of course, the images spread online faster than spilled milk … and Shatner finds the reaction pretty great, telling us it’s a good reminder to say “yes” to opportunities.

That said, you won’t actually see Shatner driving and dining in the commercial itself. Instead, he tells us much of the ad features him in a spaceship … a clear nod to his real-life trip to space aboard a Blue Origin rocket.

Shatner admits the ad agency had a tough assignment … figuring out how to sell a commercial centered around having enough fiber to go to the bathroom in an amusing way — but he says they pulled it off.