A famed French diver known as 'Mr. Titanic' is one of the passengers on board the missing submersible

• A veteran deep sea diver is on board the missing submersible that tours the Titanic shipwreck.
• Paul-Henry Nargeolet, known as "Mr. Titanic," has visited the shipwreck site at least 35 times.

A former French navy captain and veteran deep sea diver known as "Mr. Titanic" has been identified as among the passengers on board the missing submersible that was headed to the shipwreck site of the RMS Titanic in the depths of the North Atlantic.

Explorer Paul-Henry Nargeolet, 77, has visited the wreck site of the iconic passenger liner that sank in 1912 after it hit an iceberg on its maiden voyage at least 35 times.

Nargeolet's spokesman told the BBC that the famed diver was one of the five people on board the 21-foot OceanGate Expeditions sub, which went out of contact on Sunday morning during a dive to the shipwreck site that lies 12,500 feet below the surface of the ocean.

Mathieu Johann, Nargeolet's spokesman, told the BBC that he hoped the crew on board the missing submersible would be reassured by Nargeolet's poise and military background as search-and-rescue teams continue to work in a race against time to locate the vessel.

Nargeolet is aboard the missing OceanGate Expeditions sub with passengers Hamish Harding, a British billionaire, British businessman Shahzada Dawood, and his son Suleman.

The Telegraph reported that Nargeolet was part of the first human expedition to visit the wreck site of the Titanic in 1987 after it was discovered two years earlier in an expedition led by oceanographer Robert Ballard.

"It was absolutely unbelievable," Nargeolet told Forbes in a 2012 interview of the first time he laid eyes on the sunken passenger liner while on board a manned submersible.

"Usually, on the submersibles, everyone is talking, there is always noise. But as we approached the bow, we all went silent," Nargeolet said at the time, adding, "There was absolutely no sound in the sub. I was in awe."

As he gazed upon the Titanic wreckage, Nargeolet said he "could almost see the people walking in the deck."

Additionally, Nargeolet and his team mapped the 3-by-5-mile span of the Titanic debris field for the first time with the help of sonar and more than 130,000 photos taken from robotically-controlled underwater devices, according to Forbes.

Nargeolet warned of the dangers of deep sea diving and visiting the Titanic wreck site during a 2019 interview with the Irish Examiner, saying, "You're dead before you realize that something is happening."

"If you are 11m or 11km down, if something bad happens, the result is the same," Nargeolet told the newspaper at the time. "When you're in very deep water, you're dead before you realize that something is happening, so it's just not a problem."

Nargeolet, who is skilled in piloting submersibles and is a highly experienced diver, once broke the record for deepest submersible dive at 35,853 feet below the surface, according to the Irish Examiner.