Still photos taken from the world's first moving images of the mysterious giant squid in its natural habitat have been released by documentary filmmakers in conjunction with Japanese broadcaster NHK and the Discovery Channel.

The video was shot last July, south of Tokyo, and shows a three-meter-long cephalopod.

The Zoologist at Japan's National Museum of Nature and Science, Tsunemi Kubodera, who led the 40-day expedition, says capturing the creature on video was no small achievement.

"Many people have tried to capture an image of a giant squid alive in its natural habitat, whether that's researchers or film crews. But they all failed. These are the first ever images of a real live giant squid," Kubodera told Reuters in an interview on Monday (January 7).

Kubodera succeeded in taking the first still photographs of a living giant squid in 2005, and landed another on a baited line in 2006.

"I've seen a lot of giant squid specimens in my time, but mainly those hauled out of the ocean. This was the first time for me to see with my own eyes a giant squid swimming in its deep sea habitat. It was stunning, I couldn't have dreamt that it would be so beautiful. It was such a wonderful creature," Kubodera said.

The secret to their success, was a small submersible vessel kitted out with lights invisible to both human and cephalopod eyes.

A three man team -- Kubodera, a cameraman and the submersible pilot -- drifted silently down to 630 meters and released the bait.

They then started to film, and followed the squid further into the deep to around 900 meters.

NHK will air its video footage on January 13, followed by the Discovery Channel on January 27.