Vanity Fair is reportedly reviewing the past conduct of newly hired West Coast editor Olivia Nuzzi following allegations leveled by her former fiancé that she cheated on him with ex-South Carolina Gov. Mark Sanford.

The Condé Nast-owned publication is taking another look at its decision to hire Nuzzi less than a year after she left her previous employer, New York magazine, over revelations that she had a “sexting” affair with Robert F. Kennedy, Jr., a spokesperson told the New York Times.

Vanity Fair higher-ups were reportedly concerned after Nuzzi’s ex, former Politico journalist Ryan Lizza, posted a newsletter item in which he describes how he discovered that his then-live-in girlfriend was sleeping with Sanford, who at the time was a GOP presidential candidate they were both covering.

Earlier this week, the Status newsletter reported that Vanity Fair staffers were “shocked” over the claims made by Lizza, leaving many at the company wondering whether management erred in hiring Nuzzi.

According to Lizza, Nuzzi, who wrote a piece about Sanford that appeared in the September 2019 edition of New York, appeared to have begun an affair with the former governor months after the story was published.

In the newsletter post, Lizza said he discovered a handwritten love note in her backpack that referenced “Mark,” which he believed confirmed an affair.

He claimed Nuzzi secretly followed Sanford on the trail, sent him explicit messages and photos and later admitted to a sexual encounter at Sanford’s home while telling Lizza she was tending to her sick mother.

Lizza also alleged past “messes,” including a relationship with Keith Olbermann, who he says housed and supported her while she attended Fordham.

“We were taken by surprise, and we are looking at all the facts,” the spokesperson for Vanity Fair told the Times on Friday.

Just before Lizza posted his explosive newsletter item, Vanity Fair published an excerpt from Nuzzi’s upcoming memoir, “American Canto,” in which she details how she and RFK Jr. exchanged “I love yous” — with him saying it first — and that he referred to affectionately as “Livvy.”

“I love him, I thought. Oh no. I love him so much,” she wrote.

The two also discussed the “favorite parts” of each other’s bodies — with RFK Jr. gushing about Nuzzi’s mouth while she chose Kennedy’s nose.

The news of Nuzzi’s relationship with RFK Jr, who, like Sanford, was also the subject of a profile she wrote about the then-candidate for president last year, led to her departure from New York magazine.

Ari Wilkenfeld, Nuzzi’s lawyer, told the Times: “In ‘American Canto,’ Ms. Nuzzi discusses the only instances in her long career as a journalist in which she had an improper relationship with someone she was covering.”

Wilkenfeld added that Nuzzi would “not dignify efforts to impugn her character with any future response.”

The Post has sought comment from Condé Nast, Nuzzi and Lizza.