She worked in the Trump administration, but Omarosa Manigault NewmanOmarosa Manigault NewmanJudge denies Omarosa Manigault Newman request to depose Trump, John Kelly in lawsuit Tanden seeks to defuse GOP tensions over tweets Juan Williams: The GOP's problem with women of color MORE is predicting that Joe BidenJoe BidenBiden eyes bigger US role in global vaccination efforts Trump says GOP will take White House in 2024 in prepared speech Kemp: Pulling All-Star game out of Atlanta will hurt business owners of color MORE will win the presidential election and says she'll be among those casting a ballot for the Democratic presidential nominee.

"I certainly believe that Biden-Harris will win on Tuesday," she told "Extra" in an interview Monday.

Manigault Newman — a former contestant on the Donald Trump-hosted "The Apprentice" — was hired by the then-real estate developer's campaign in 2016 and later joined the White House. She left in 2017 and published a tell-all book, "Unhinged," in 2018, which accused President TrumpDonald TrumpHarry Reid reacts to Boehner book excerpt: 'We didn't mince words' Man arrested for allegedly threatening to stab undercover Asian officer in NYC Trump says GOP will take White House in 2024 in prepared speech MORE of using racist and misogynist language about Black people and women.

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If Trump loses the White House race, he will "make life very, very difficult for us," Manigault Newman said.

"It’s going to be a tumultuous transition. Trust me," she added.

Asked by "Extra's" Cheslie Kryst if she saw a change in Trump once he entered the White House, Manigault Newman replied, "The power went straight to his head."

She called it a "special moment" to see Sen. Kamala HarrisKamala HarrisPelosi planned on retiring until Trump won election: report How Kamala Harris can find the solution for the migration crisis White House unveils official portraits of Biden and Harris MORE (D-Calif.) — like the ex-reality TV star, a graduate of Howard University — run alongside Biden as the vice presidential nominee.

When questioned about who she would be voting for, Manigault Newman said, "I don’t think you should ever ask anyone who they voted for" before telling the entertainment news show, "Just know that I voted for the graduate of Howard University, because I'm a Bison through and through!"