The survival expert took the singer out in the wilderness to see how she would handle roughing it - and during the trip, he was stung on the foot.
Thinking quickly, he asked Mel B to pee on him to help relieve the pain and she reluctantly agreed.
But during an appearance on ITV's This Morning, Bear admitted the pop star's pee didn't help.
"When you get stung by a jellyfish, the tentacles stay on it and keep stinging," he explained. "So what the urine does is stop the tentacle from continuing its stinging. It doesn't neutralise anything.
"(It didn't make) a huge difference, but I didn't want to be rude, so I was like, 'Ah, so much better. Thank you so much!'
"It helped a little bit. I mean, it wasn't the miracle cure I'd been hoping for!"