Ronan Farrow alleged that disgraced NBC News anchor Matt Lauer had a physical reaction when Farrow revealed he was working on an investigative report about "sexual harassment in Hollywood" and witnessed Lauer's use of the infamous button linked to his office door.

In a copy of his book "Catch and Kill: Lies, Spies, and a Conspiracy to Protect Predators," obtained by Fox News, Farrow recalled a conversation the two of them had in December 2016 in Lauer's office, where the then-NBC star was inquiring about the stories Farrow was pursuing, suggesting his reporting could be featured on "Today."

"There's one on Dow and Shell seeding California farmlands with toxic chemicals," Farrow said as Lauer apparently focused on his computer monitor. "There's a series on addiction, one on truck safety reforms being blocked by lobbyists, and one about sexual harassment in Hollywood."

RONAN FARROW'S 'CATCH AND KILL' 'MOTIVATED NOT BY A PURSUIT OF TRUTH, BUT AN AXE TO GRIND,' NBC NEWS PRESIDENT SAYS IN LEAKED MEMO

Farrow, who was an NBC News employee at the time, then wrote that Lauer's eyes "snapped back to me," but acknowledged he wasn't certain which story "caught his attention."

"It's for a series about undercovered stories in Hollywood," Farrow continued. "Pedophilia, racism, harassment ..."

"They sound terrific," Lauer responded.

MATT LAUER CLAIMS SECRET DOOR-LOCKING BUTTON AT NBC OFFICE 'DIDN'T EXIST'

The conversation then shifted to Farrow's aspirations as a journalist and how he'd like to anchor in the future, to which Lauer replied, "That's what you think you want."

Farrow had been scheduled to fill in for Lauer and other anchors during the week of Christmas, so Lauer offered pointers. Then their conversation neared its end.

"You want this closed?" Farrow asked about Lauer's office door.

"I've got it," Lauer answered.

Farrow saw Lauer pushing a button on his desk, which swung the door shut.

Last week, Lauer denied he had a button that "could lock the door from the inside." He also denied he raped an NBC employee, an allegation included in Farrow's book.

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"Despite numerous erroneous reports in the past, there was not a button in my office that could lock the door from the inside. There was no such locking mechanism. It didn’t exist,” Lauer wrote. “It would have been impossible to confine anyone in my office, for any purpose, and I have never attempted to make anyone feel as if they were confined in my office. I have never assaulted anyone or forced anyone to have sex. Period."

Farrow's book is set to be released on Tuesday.

Fox News' Brian Flood contributed to this story.