During the 2016 presidential campaign, Fox News host Megyn Kelly was one of the networks most popular hosts, and executives thought of her as the network's star of the future. Kelly held her own against then-presidential candidate Donald Trump in a nationally televised Republican debate, and drew increasingly high ratings on her nightly show, The Kelly File.

But by the start of 2017, Kelly was suddenly out, announcing on Facebook that she made the decision to leave the network that made her famous to join NBC News.

The move came in the aftermath of accusations she made in her book Settle for More about being a victim of sexual abuse from former Fox News Chairman Roger Ailes. Ailes was ultimately ousted from the network over multiple cases of alleged misbehavior towards female staffers, which included a lawsuit from Kelly's former colleague, Gretchen Carlson.

Most observers assumed her decision to leave Fox News was largely due to her experience dealing with harassment from Ailes, but in a New York Times report, Bill O'Reilly reportedly played a large role in causing Kelly to abandon a network that had offered her upwards of $2o million a year.

O'Reilly is currently embroiled in his own scandal following the revelation he paid millions of dollars to five former Fox News personalities to settle claims of verbal and sexual harassment. The embattled host abruptly announced he was going on vacation last week following the loss of over 60 advertisers from his popular show, The O'Reilly Factor.

Kelly's beef with O'Reilly came after a 2016 interview on CBS This Morning, when O'Reilly took exception to Kelly's comments about Ailes and defended Fox News against the claims made in her book.

"Look, it's open season," an irritated O'Reilly told CBS host Norah O'Donnell. "Let's whack the Fox News Channel. I've had enough of it. It's a good place to work. All right?"

According to Times reporters Emily Steel and Michael Schmidt, O'Reilly's comments angered Kelly, who shot off an email to executives at the network to complain that O'Reilly's words could cause future victims of harassment at the network to remain silent.

Despite the email, O'Reilly brought up the interview later that day on The O'Reilly Factor and appeared to rip both Kelly and women who claimed to be victims of misbehavior at Fox News.

"That experience, along with a deep skepticism about whether the network was truly committed to changing its culture after Mr. Ailes was forced out, was a factor in Ms. Kelly's decision to leave Fox News for a new role at NBC News, according to two people familiar with the matter," the Times reported.

Neither Kelly or Fox News immediately responded to a request to comment.

"Mr. O'Reilly cannot comment on what Megyn Kelly thought, or did or did not do, except to say she never raised any such issue with him, nor did anyone else," said Marc E. Kasowitz, a lawyer for O'Reilly. "At this time, it is apparent to any objective observer that Mr. O'Reilly is being subjected to a malicious campaign intent on harming his reputation and family through speculation and innuendo."

O'Reilly remains on vacation, with the future of his role at the network up in the air. A spokeswoman for Fox News says O'Reilly will return April 24, but multiple reports say the Murdoch family is awaiting the results of an investigation of his behavior by the law firm Paul, Weiss, Rifkind, Wharton & Garrison before deciding the popular host's fate.

Kelly was most recently seen hanging out with new colleagues Savannah Guthrie and Lester Holt at The Hollywood Reporter's 35 Most Powerful People in Media party.

NBC has yet to announce when Kelly will officially start her new show, slated for 9 a.m. on weekdays, though Guthrie said Kelly is "supposed to start some time in May or June." The network also canceled the 9 a.m. hour of the Today show to make room for Kelly, causing Temple grad Tamron Hall to leave the network.

Kelly, who will also host a yet-unannounced Sunday Night show on NBC, is eager to get started.

"I've spent enough time staring at the refrigerator, it's time to do some news," Kelly told the Hollywood Reporter.