The Durban-born forward was fishing with his younger brother, Keagan, 27, off his local beach in KwaZulu- Natal, when his rod bent over double.
When he reeled it in after an almighty battle, he found to his shock a 2.1m shark had taken his bait - and it was one of the most dangerous species swimming the seas: a Zambezi shark, also known as a bull shark.
The brothers were determined to unhook the shark and return it safely to the Indian Ocean, but huge waves had washed it high up on to the sandy beach and stranded it there.
So “Madcap Kyle” and Keagan decided there was only one thing for it - they would have to drag it back down the beach and swim it back out to sea.
The incredible video - believed to have been shot by their dad, Shane - shows Kyle lassoing a strap around the shark’s tail fin and the brothers then drag the man-eater down the beach.
Both battle as huge waves crash over them and threaten to beach the shark again, but after 30 seconds they get it into deeper water and turn the shark around to face the ocean.
Waves crash over their heads, completely submerging them, as they hang on to the shark, often completely out of their depth.
Between waves, they hold the carnivore and allow seawater to rush through its open mouth and gills until they feel it regain its strength.
When the shark is finally ready, it kicks its tail and heads off swiftly, back out through the surf and into calmer waters, where it would have resumed its search for dinner.
A friend of Kyle’s said: “It was such a crazy thing to watch these two walking a shark that could have bitten their arms or legs off in one bite out to sea, then swimming with it.
“Kyle had caught it and felt responsible for getting it back into the ocean as quickly as possible, and the only way to do that was to get in the water with the shark itself.
“Everyone was holding their breath, but the boys pulled it off and then high-fived each other when the shark was safely on its way and you could see the fin beyond the wave line.
“Kyle and Keagan cracked open a beer as soon as they were back on the beach and it’s fair to say they were both pretty full of adrenalin and had a good laugh about it.
“Kyle said his coaches told him to keep fit during his break, but I doubt that was their idea of pre-season training,” she said.
Kyle had spent his five weeks’ season break drone fishing with his brother.
Keagan is a drone racing instructor and they used a large remote-controlled drone to fly their mullet bait out to sea to drop it where the big fish were feeding.
Kyle’s father posted the video on his Facebook page where it has gone viral with more than 75000 hits and said: “When an animal’s life needs to be saved you do what you have to do.
“God will keep you safe. Proud of the boys. No place for pussies. One happy Zambezi shark.”
Ironically, hooker Kyle played Super Rugby for the aptly named Sharks team based in Durban, before being poached by Newcastle Falcons. He joined the top English club in 2016.