A TV crew for the Animal Planet show "River Monsters" discovered a castaway on a deserted island off the coast of Australia.

While filming for the reality show, "River Monsters" host Jeremy Wade and his crew spotted a man.

"He had said his last prayer," Stephen Shearman, the director of the episode "Death Down Under" told Inside Edition. "He was prepared to die and meet his maker."

According to Shearman, the crew had not even planned on filming in the area they discovered the castaway. They were searching for the "giant grouper" fish in the waters of Barranyi North Island.

When the waters were too choppy to film at the original location, they decided to move to the other end of the island.

They jokingly said to one another that they may discover a castaway like Tom Hanks in the 2000 movie "Cast Away."

That's when they discovered a "guy with no clothes was running out of the cave, waving his arms out."

The man they found was an experienced Australian fisherman named Tremine who had ventured off his boat to find better oysters.

"He had tried to walk back, got beaten by the sun, and made his way back to the beach," Shearman said. "Meanwhile, he had suffered from sunstroke and was unable to go any further. He then spent that first night on the beach, and the next morning he tried again, but the sun had gotten to be too much for him, and at this point, he is now trapped."

According to Shearman, the man had been stranded for 60 hours. They gave him water and hydration pills but he threw them up.

"His body wasn't ready for that at all. His condition was quite serious," he said.

He eventually made a full recovery. Shearman said the experience was "sobering."

"I've made a lot of shows involving survival, but to see it first hand and to see the real shocking powers of what three days without water can do was really sobering," Shearman said.

The episode featuring the castaway discovery aired last week. Watch "River Monsters" on Thursdays on Animal Planet.