Veteran journalist Bob Woodward admitted to losing a tape of an interview he and former Washington Post colleague Carl Bernstein conducted with Donald Trump decades before he became president.

The two iconic Watergate investigative reporters revealed Monday that the file of their late 1980s discussion with Trump was the only one Woodward ever misplaced.

"We went to visit him in the late 1980s," Bernstein said at CNN's "Citizen" conference. "We had been at an evening that we was present at and he said, 'Wouldn't it be great if you guys came up and interviewed me.' And we went to his office. We can't find the tape now."

"But it was classic Trump," he added.

Woodward went on to explain that he had no interest in speaking with the Manhattan businessman, but Bernstein convinced him otherwise.

"It was classic Bernstein because your instinct was, 'We've gotta go talk to this guy.' I said, 'Why?' I mean what do you — and you said well he had written The Art of the Deal and he was in technicolor at the time," Woodward said.

"It's the only file you've ever lost in your whole life," Bernstein noted.

"Yea, yea. That's right," Woodward replied.

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Woodward is known for gathering records to back up his writing.

For instance, for his recently released book on the chaos within the West Wing, titled Fear: Trump in the White House, he said he transcribed hundreds of hours of interviews he had conducted.

Trump called Woodward's book a "scam" with misquotes.