Omarosa Manigault Newman claims that Donald Trump questioned Harriet Tubman's appearance after the then-White House aide approached him about putting the famous escaped slave and abolitionist on the $20 bill
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Donald Trump‘s cutting insults about women’s appearance are extensive and well-documented but Omarosa Manigault Newman managed to dig up an untold alleged affront for her new tell-all book, Unhinged, out Tuesday.

Manigault Newman claims that Trump questioned Harriet Tubman’s appearance after the then-White House aide approached him about an Obama-era initiative to put the famous escaped slave and abolitionist on the $20 bill, replacing Andrew Jackson.

Manigault Newman says she wrote a decision memo about the matter and brought it to Trump.

Then, Manigault Newman describes, “He came to the picture of Tubman, the woman who personally brought more than 300 slaves to freedom, risking her own life every time, and said to me, ‘You want to put that face on the twenty-dollar bill?’ ”

Trump has made similar comments about women in the past. During his presidential campaign in 2015, he criticized rival Carly Fiorina’s physical appearance in an interview with Rolling Stone magazine.

“Look at that face! Would anyone vote for that? Can you imagine that, the face of our next president?” Trump said. (Trump never apologized but later backed away from his comments, saying Fiorina had a “beautiful face.”)

And after PEOPLE writer Natasha Stoynoff accused Trump in 2016 of forcing an unwanted kiss on her, he denied the allegations and hinted that he wouldn’t have sexually assaulted Stoynoff because he didn’t find her attractive. “Look at her … I don’t think so,” he said at the time.

RELATED VIDEO: PEOPLE Writer Natasha Stoynoff Breaks Silence, Accuses Donald Trump of Sexual Attack

In the same chapter of her book, Manigault Newman references 2016 reports that Trump fired Khloe Kardashian from Celebrity Apprentice in 2009 over her weight.

“According to anonymous Apprentice staffer sources, he’d called her a ‘fat piglet’ and bemoaned that they didn’t book ‘the hot one,’ referring to Khloe’s sister Kim Kardashian,” Manigault Newman writes. Trump has never commented on the reports.

Kardashian responded to his alleged comments at a press conference in 2016, saying, “I didn’t think he was saying those things about me. But he says those comments about a lot of women — really derogatory things. Someone who is that simplistic to judge things off of surface is not someone I want running my country.”

But Manigault Newman writes that Trump actually fired Kardashian because she’d been arrested for a DUI in the past. Manigault Newman says that while fellow contestant and Trump friend Dennis Rodman’s drinking was forgiven, “Trump didn’t have the same compassion for Khloe Kardashian … Khloe was taken to task on national television about her arrest and fired.

“I believe sexism played a part, but I also believe Donald was a little jealous of the Kardashians’ fame,” Manigault Newman adds.

As the shocking claims from Manigault Newman’s new book continue to make headlines, the president’s campaign announced on Tuesday that it has filed for arbitration against the former White House aide for allegedly breaching a 2016 nondisclosure agreement, according to CNN.

Press secretary Sarah Huckabee Sanders also issued a statement saying that the tell-all “is riddled with lies and false accusations,” adding that “it’s sad that a disgruntled former White House employee is trying to profit off these false attacks, and even worse that the media would now give her a platform, after not taking her seriously when she had only positive things to say about the President during her time in the administration.”

And within the past 24 hours, President Trump has taken to Twitter in a rage, tweeting that Manigault Newman, who was fired from her White House position in December 2017, is a “dog” and has “zero credibility.”