With 23 Olympic gold medals, swimmer Michael Phelps needed a new challenge.

And what better challenger for the most decorated Olympian in history than the ocean's most fearsome predator - the Great White Shark.

Backed by a 15-strong army of divers underneath him for protection, he emulated the shark’s shape and swimming conditions while racing over 100m.

Viewers in the US tuned in to the Discovery Channel on Sunday night to see the results of this amphibious battle to end all battles.

So did Phelps win the ultimate contest of human conditioning and skill versus pure, survival of the fittest evolution... or did he become lunch?

For starters, much to the disappointment of some viewers, Phelps, 32, didn't actually race a real shark.

Instead, the swimmer was pitted against three computer generated sharks - a hammerhead, a reef shark and, last but not least, a Great White.

Incredibly, Phelps did actually beat one of the sharks.

Sadly, his skills were no match for the Great White, which was two whole seconds faster over 100m.