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TOKYO — Haruo Nakajima, the actor who stomped in a rubber suit to portray the original 1954 Godzilla, helping to make the Japanese monster an iconic symbol of the nuclear era, has died. He was 88.

Nakajima's daughter Sonoe Nakajima told The Associated Press on Tuesday that he had been hospitalized last month and died of pneumonia Monday.

Haruo Nakajima was a stunt actor in samurai films when he was approached to take the role of Godzilla, which may be Japan's most successful cultural export. Some fans prefer Nakajima's version over some Hollywood depictions which they say make the fire-breathing lizard an evil-looking animal.

Japanese actor Haruo Nakajima speaks behind a gold statue of Godzilla at an exhibition in Tokyo in 2014. AFP - Getty Images

Vivacious and energetic in a 2014 interview with The Associated Press, Nakajima said he invented the character from scratch, and developed it by going to a zoo to study how elephants and bears moved. He said it was important to show the pathos of the creature, which could only smash everything in its way.

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"If Godzilla can't walk properly, it's nothing but a freak show," he said at his suburban Tokyo apartment, proudly sitting among sepia-toned photos of him as a young man and Godzilla figures.

He recalled that the rubber suit he wore was so hot, especially under the glaring lights of the movie set, that the sweat he wrung from his shirt would fill half a bucket.

In the original movie, directed by Ishiro Honda with an unforgettable score by Akira Ifukube, Godzilla surfaces from the Pacific Ocean suddenly, a mutation as a result of nuclear testing in the area.

Godzilla in the 1954 film. Courtesy of Everett Collection

The Toho classic, which went on to become a mega-series and inspired Hollywood spinoffs, struck a chord with postwar Japan, the only nation in the world to suffer atomic bombing, in Hiroshima and Nagasaki in the closing days of World War II.

Nakajima said the theme of his Godzilla was grand and complex, addressing universal human problems, as it spoke to a Japan that still remembered wartime suffering.

"It's not some cowboy movie," he said.

Although recent Godzilla films use computer graphics, the latest Japanese Godzilla remake, released last year, went back to using a human actor, Mansai Nomura, a specialist in the traditional theater of Kyogen. His movements were duplicated on the screen through "motion capture" technology.

Godzilla memorabilia is displayed in the home of actor Haruo Nakajima in Sagamihara, Japan on April 28, 2014. Junji Kurokawa / AP file

Until recently, Nakajima had continued to be a star guest at festivals and events. He had been scheduled to be featured at the Tokyo International Film Festival in October.

"I am the original, the real thing," he said in 2014. "My Godzilla was the best."

A funeral is to be held for family and close friends.