Long-distance ocean swimmer Adam Walker was halfway through his 25-kilometer trek across New Zealand's Cook Strait last week when a pod of dolphins showed up to protect him from the great white shark swimming below.

The British athlete is set to become the first man to complete the Ocean's Seven - a group of seven long-distance swims around the world. Walker was swimming the approximately 16-mile long Cook Strait when he spotted the shark lurking below him.

Almost immediately, Walker said, according to ABC News, about 10 dolphins surrounded him and stayed with him for over an hour, seemingly serving as his protectors.

"I'd like to think they were protecting me and guiding me home," Walker wrote on his Facebook page. "This swim will stay with me forever."

A crew on his assist boat captured the event on video and posted it on YouTube the next day, April 23, and has since had more than 3 million views.

According to a related Good Morning America report, dolphins supposedly ward off sharks with their high-pitched sounds.

Walker, a swim coach, finished swimming the Cook Strait, the sixth leg of the Ocean's Seven, in 8 hours and 36 minutes. He has already conquered the English Channel, Gibraltar Straits, Catalina Channel, Molokai Strait and Tsugaru Strait.

The North Channel in the Irish Sea is the seventh and final step of the Ocean's Seven marathon - one which only four people in the world have completed - the ABC report said. He will attempt the Irish swim in August, according to his YouTube page.

After Walker's incredible dolphin-assisted swim, he fittingly is swimming to raise money for the Whale and Dolphin Conservation, an organization that calls itself "the leading global charity dedicated to the conservation and protection of whales and dolphins."