Former White House chief of staff Mick Mulvaney endorsed South Carolina Rep. Nancy Mace over her Republican primary challenger backed by former President Trump.

Mace announced she had received Mulvaney’s endorsement in a Monday press release, where the former Trump White House chief backed the congresswoman as "a proven fiscally conservative leader for South Carolina and the Lowcountry."

"Getting things done in Washington isn’t easy and it doesn’t have to be a nasty business – especially when Members of Congress put their constituents’ needs before partisan politics," Mulvaney said. "The fact Congresswoman Mace held over 1,000 meetings in the district in her first year in office shows how she is dedicating everything she has to the Lowcountry."

REP. NANCY MACE PUSHES BACK AFTER TRUMP ENDORSES GOP PRIMARY CHALLENGER IN SOUTH CAROLINA

Mick Mulvaney

In this Oct. 17, 2019, file photo, acting White House chief of staff Mick Mulvaney speaks in the White House briefing room in Washington.  (AP Photo/Evan Vucci)

"Her voting record is exceptional when it comes to promoting smaller government and lower taxes," he continued. "And refreshingly, actually she works overtime to get things done in Congress. I support her 100 percent."

Mace praised Mulvaney, a former South Carolina congressman himself, as having "served his country and our state with distinction and honor."

"He is a proven fiscal conservative leader. He knows how difficult it is to flip a seat and then keep it," Mace said in the release. "Mick understands putting your constituents first sometimes means bucking the party line and that principles matter."

Rep. Nancy Mace, a Republican from South Carolina, speaks to members of the press outside the U.S. Capitol in Washington, D.C., on Thursday Oct. 21, 2021.  (Sarah Silbiger/Bloomberg via Getty Images)

"Mick has stood up time and time again to do the right thing, he’s a great example of what conservative leadership looks like in South Carolina," she continued.

Mace pushed back against Trump’s endorsement of Katie Arrington, her primary opponent, in a video posted earlier this month.

"I remember in 2015 when President Trump announced his run, I was one of his earliest supporters. I actually worked for the campaign in 2016. I worked at seven different states across the country to help get him elected," Mace said in a video in front of Trump Tower in New York City.

President Trump speaks at a campaign rally at HoverTech International, Monday, Oct. 26, 2020, in Allentown, Pennsylvania.

President Trump speaks at a campaign rally at HoverTech International, Monday, Oct. 26, 2020, in Allentown, Pennsylvania.  (AP Photo/Alex Brandon)

"I supported him again in 2020 because of policies I believed in," Mace said. "He brought American jobs back. He lowered our taxes… he made America safer and took on China directly."

Trump called Mace "an absolutely terrible candidate" when endorsing Arrington earlier that week. The former president also claimed Mace was "not at all representative of the Republican Party to which she has been very disloyal."

Mace, in her video, noted that "I won this seat back for Republicans in 2020," and taking aim at Arrington, she argued, "If you want to lose this seat once again in the midterm election cycle to Democrats, then my opponent is more than qualified to do just that."

Katie Arrington campaigning in Mt. Pleasant, South Carolina, on Sunday.

Katie Arrington campaigning in Mt. Pleasant, South Carolina, on Sunday.  (David Weigel/The Washington Post via Getty Images)

Mulvaney’s and Trump’s dueling endorsements show an apparent divide between the ex-White House chief and his former boss.

The apparent disparity between Mulvaney and Trump also offers Democrats more ammunition in trying to craft a narrative of Republican dissonance as momentum for a red wave builds ahead of the 2022 midterm elections.

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It also comes after Republicans in Virginia won back the top three statewide seats from the Democrats with Gov. Glenn Youngkin leading the ticket with a big-tent approach that included a Trump endorsement.

The Virginia election wins have been pointed to by many political commentators as a bellwether for a surge in Republican elections in November.

Fox News' Paul Steinhauser contributed to this report.