Former NBC anchor Matt Lauer, once one of the highest-paid journalists on US television, has denied a former colleague's rape claim in a new book.
Former TV producer Brook Nevils alleges the attack in Catch and Kill, by investigative journalist Ronan Farrow.
Mr Farrow writes that Mr Lauer invited Ms Nevils to his room where he forcibly kissed and raped her.
Mr Lauer - who lost his job in November 2017 - called the allegations "dangerous and defamatory".
In a statement, Ms Nevils responded to Mr Lauer's denial, calling it a "case study in victim shaming".
"There's a Matt Lauer that millions of Americans watched on TV every morning for two decades. And there is the Matt Lauer who this morning attempted to bully a former colleague into silence," she said to NBC.
WARNING: This report contains disturbing details.
What is the allegation?
Farrow's new book Catch and Kill details a new claim from Ms Nevils, the previously unnamed former NBC News employee whose complaint led to Mr Lauer getting fired from NBC's morning show Today.
Ms Nevils says that when they were covering the 2014 Sochi Winter Olympics in Russia, Mr Lauer invited her to his hotel room after a night of drinks.
Once in the suite, she says, he pushed her against the door and kissed her, according to Variety magazine, which has seen Mr Farrow's book.
She says he shoved her on to the bed and anally raped her.
She said: "It was non-consensual in the sense that I was too drunk to consent.
"It was nonconsensual in that I said, multiple times, that I didn't want to have anal sex."
Her sexual encounters with Mr Lauer continued when they both returned to New York.
"This is what I blame myself most for," Ms Nevils said.
"It was completely transactional. It was not a relationship."
How has Matt Lauer responded?
In a lengthy letter issued by his lawyer to Variety, Mr Lauer said he has refrained from speaking out until now on such "false and salacious allegations" in order to protect his children.
He rubbished the claim as "part of a promotional effort to sell a book".
He continued: "It is alleged that an extramarital, but consensual, sexual encounter I have previously admitted having, was in fact an assault.
"It is categorically false, ignores the facts, and defies common sense."
He continued: "There was absolutely nothing aggressive about that encounter."
Mr Lauer concludes: "I have never assaulted anyone or forced anyone to have sex. Period."
In her response to his statement, Ms Nevils hit back at Mr Lauer and the "threats, bullying... shaming and predatory tactics" he "has tried to use against me".
Mr Lauer was co-host of NBC's flagship Today programme for two decades.
Shortly before his dismissal, he had signed a new contract with the network worth a reported $20m (£16m) annually.
How did the complaint come to light?
According to Mr Farrow, Ms Nevils did not report the incident until 2017 as the #MeToo movement gained strength.
Ms Nevils filed a formal complaint with NBC's office of human resources at the urging of former Today show co-anchor Meredith Vieira.
Mr Lauer was fired the next day.
But Ms Nevils told Mr Farrow that she soon learned NBC News executives were "emphasising that the incident had not been 'criminal' or an 'assault'".
She took a leave of absence in 2018, before leaving the network.
Mr Farrow writes in his book: "NBC proposed a script she would have to read, suggesting that she had left to pursue other endeavors, that she was treated well, and that NBC News was a positive example of sexual harassment."
How has NBC responded to the latest allegation?
In a statement on Wednesday, NBC said: "Matt Lauer's conduct was appalling, horrific and reprehensible, as we said at the time.
"That's why he was fired within 24 hours of us first learning of the complaint. Our hearts break again for our colleague."
Speaking on NBC's morning show on Wednesday, anchor Savannah Guthrie - Mr Lauer's former co-host - called the new revelations "shocking and appalling".
Hoda Kotb, who was announced as Mr Lauer's replacement in early 2018, echoed Ms Guthrie.
"We don't know all the facts in all of this, but they are not allegations of an affair, they are allegations of a crime," she said.
Mr Farrow's book also accuses NBC, which formerly employed him, of obstructing his investigation into Hollywood producer Harvey Weinstein.
His reporting, ultimately published in the New Yorker magazine, brought about the downfall of Mr Weinstein and won Mr Farrow a Pulitzer.
Mr Weinstein has been criminally charged and denies all accusations of nonconsensual sex.