Justin Long Once Pooped the Bed While Wife Kate Bosworth Slept Next to Him

Justin Long's dropping a major bombshell ... about dropping a deuce IN his bed while his wife, Kate Bosworth, was snoozing next to him -- and ya gotta hear why he calls it a romantic moment!

The actor shared the wild story on the "PIE with Kurt Sutter and Katey Sagal" podcast Tuesday ... recalling how he once unintentionally gave Kate a pungent wake-up call by soiling the bed during a food poisoning fiasco in Mexico City.

Justin described feeling so ill before the incident that he was hooked up to an IV, which Kate had in hand as she trailed behind him to the bathroom -- a moment JL compared to a scene straight out of "Dumb and Dumber."

But then things took a wild turn, as JL recalled, "At one point that night, I woke up, and there's no other way to say this, I can't dance around it: I had s*** the bed. I had s*** the bed, and she was in the bed."

While most partners would be fleeing, Justin credited Kate for giving him loads of TLC during that embarrassing moment ... recalling how she wasn’t judging him at all.

He says, "I was s***ting my brains out, and she was looking at me lovingly, and I thought: 'This is really romantic.'"

It didn’t stop there -- she even encouraged him to take a shower after the incident when all he wanted was to stay in bed. Then she called the doc, and after all that, he crawled back into bed, carefully avoiding the poop-stained spot.