CNN host Don Lemon’s history of alienating female co-workers during nearly two decades at the all-news cable channel includes telling Soledad O’Brien that she wasn’t really black and calling a female producer fat to her face, according to a bombshell report.

Lemon, who was recently forced to undergo sensitivity training after he made sexist comments on the air about GOP presidential candidate Nikki Haley’s age, is described in a damning exposé by Variety as a malcontent who frequently engaged in “diva-like behavior.”

According to Variety, Lemon sent threatening, anonymous text messages to colleague Kyra Phillips because he was jealous that she was assigned to cover the aftermath of the US invasion of Iraq.

“Now you’ve crossed the line, and you’re going to pay for it,” read one message sent to Phillips’ phone from an anonymous number that was later reportedly traced to Lemon.

According to Variety, CNN, which conducted an investigation of the texts, removed Lemon from his co-anchoring duties alongside Phillips and demoted him to weekends.

“Don says the incident never occurred and that he was never notified of any investigation,” a spokesperson for Lemon told The Post. “CNN cannot corroborate the alleged events from 15 years ago.” 

A CNN spokesperson told The Post: “The story, which is riddled with patently false anecdotes and no concrete evidence, is entirely based on unsourced, unsubstantiated, 15-year-old anonymous gossip.”

“It’s amazing and disappointing that Variety would be so reckless,” the CNN spokesperson said.

Lemon is also alleged to have mocked former CNN and Headline News anchor Nancy Grace on the air by mimicking her, according to Variety.

Variety quoted “a person close to” Grace as saying that the former anchor “thinks [Lemon is] an ass” because he was always “rude, dismissive, and really unfamiliar with the [news] content being discussed.”

“That was the beginning of when you knew that Don was kind of volatile and didn’t say good things about women,” one person who is reported to have witnessed Lemon mocking Grace told Variety.

Lemon was also known around the company as someone who was wont to bend the rules.

Just a year after joining CNN in 2006, the then-41-year-old Lemon started dating a 22-year-old junior staffer despite the disparity in age as well as the power dynamic.

In 2008, Lemon was reportedly upset that O’Brien was picked to host a documentary series titled “Black in America.”

In an editorial call that was attended by some 30 staffers, Lemon allegedly suggested that O’Brien, whose father was a white and whose mother is Afro-Cuban, wasn’t black.

“Don, Soledad, and others, have in the past correctly referred to her Afro-Cuban heritage as it is a unique part of her personal story,” a CNN spokesperson told The Post.

“But Don denies making any related remark in a derogatory way.”

O’Brien told Variety: “Don has long had a habit of saying idiotic and inaccurate things, so it sounds pretty on brand for him.”

CNN insiders told Variety that Lemon, who reportedly showed up late to the newsroom and skipped editorial meetings, was allowed to skirt the rules because of his close friendship with Turner Broadcasting chairman and CEO Phil Kent.

Lemon also had the backing of Jeff Zucker, who was hired to run CNN in 2013.

Six months after Zucker’s arrival, Lemon gave a controversial on-air monologue in which he told black people to “pull up your pants.”

“Walking around with your ass and your underwear showing is not OK,” Lemon said during the broadcast.

“In fact, it comes from prison when they take away belts from the prisoner so that they can’t make a weapon.”

Lemon added: “And then it evolved into which role a prisoner would have during male-on-male prison sex.”

“The one with the really low pants is a submissive one. You get my point.”

Goldie Taylor, a former CNN consultant, said she was blacklisted by the network for criticizing Lemon’s comments. 

“I’m not going to weigh in on the network’s booking practices of unpaid guests a decade ago,” a CNN spokesperson told The Post.

Lemon also drew sharp criticism when it was learned he had given advice to Jussie Smollett, the disgraced actor who fabricated claims that he was the victim of a Chicago gang assault by a mob of Trump supporters.

“CNN reviewed the incident in question at the time and found that any interaction was an act of journalism as Don was attempting to prompt a response from Mr. Smollett and book him for his show,” a spokesperson for the network said.