An Italian diver has captured the moment he swam with a huge whale shark during a spearfishing day in the Persian Gulf.

In remarkable footage, Federico Erroi says that he saw a huge shadow 20 metres beneath the surface of the water on his way back to his boat and immediately dived towards it.

For a brief moment he swims alongside the whale, holding its fin.

"When my eyes saw the huge whale shark, my heart started pounding," Erroi explains. "It was like a dream: me and a whale shark swimming together in the silence of the Persian Gulf."

On his YouTube channel, Erroi describes the moment further: "My heart is pumping, my hands starts to shake, eyes full of joy, in front of one of the giant animals in the world.

"We danced together in the silent world, no words can explain every single emotion felt in that few seconds when my hand grabbed ... his fin."

The whale shark is the largest fish in the sea and is classified as an endangered species.

Experts have said that while it is fun to swim with whale sharks, it is not recommended that divers catch rides by hanging onto their fins.