Shizuhiko Haraguchi served as a gunnery officer on the Musashi, one of the largest battleships in history, when it was being fitted in Japan before it departed for the Pacific in 1943.
He said he recognised underwater photos taken by Allen's team of a large gun turret and a catapult system used to launch planes.
"I recognised that main turret, which I was assigned to," Haraguchi, 93, said in a telephone interview from his home in Nagasaki in southern Japan where the ship was built, fitted and tested. "I felt very nostalgic when I saw that."
The Musashi had nine 46-centimeter guns, which were each 20 metres long, he said.
Allen said his team found the battleship at a depth of 1 kilometer in the Sibuyan Sea using an autonomous underwater vehicle following more than eight years of study.
Historians and military experts praised the apparent discovery of the legendary battleship after 70 years, saying it would help promote interest in World War II studies. A group supporting navy veterans said survivors would want to hold a memorial service at the site.
Haraguchi left the ship just before its departure because he was transferred to an aviation unit in eastern Japan.
The discovery on Sunday of the battleship comes as the world this year marks the 70th anniversary of the war's end.
The naval battle, considered the largest of World War II, crippled the Imperial fleet, cut off Japanese oil supplies and allowed the US invasion of the Japanese-held Philippines.
"The discovery of the Musashi was really a nice surprise," Haraguchi said. "It was as if the spirits of her crewmembers who sank with her were telling us to remember them for the 70th anniversary."