Georgia Gov. Brian Kemp set to tap Kelly Loeffler for soon-to-be open Senate seat, defying President Trump

Georgia Gov. Brian Kemp is poised to tap businesswoman and Republican donor, Kelly Loeffler, as his appointment to the U.S. Senate, according to a source with direct knowledge of the decision, in a move that defies President Donald Trump's own wishes for the soon-to-be open seat.

Kemp's decision could potentially face sharp backlash from President Trump, who in the past weeks has called Gov. Kemp multiple times to push for him to pick Rep. Doug Collins, Ranking Member of the House Judiciary Committee and a staunch supporter of his in the ongoing impeachment probe, according to sources familiar with the effort, and his key allies.

Earlier on Monday, the president tweeted his admiration for Collins. "Great job by @RepDougCollins of Georgia over the weekend in representing the Republican Party, and myself, against the Impeachment Hoax!"

The governor began informing lawmakers about his decision over the weekend, according to the source.

An official announcement is expected on Wednesday, a source said. A spokesperson for Kemp's office declined to comment.

The anticipated selection of Loeffler, the co-founder and CEO of Bakkt and a co-owner and co-chair of the WNBA's Atlanta Dream team, was first reported by the Atlanta Journal Constitution.

The Atlanta businesswoman is set to fill longtime GOP Sen. Johnny Isakson’s Senate seat, who is retiring at the end of 2019, in the new year. After serving for three terms, Isakson, 74, announced in August he was stepping down at the end of the year due to health issues.

Isakson is slated to deliver his farewell address on the Senate floor on Tuesday.

The temporary appointment will serve until a special election is held on Nov. 3, 2020, alongside Georgia's other Senate seat up for grabs in 2020.

In the lead-up to Kemp's expected announcement, hundreds of Georgians submitted applications to be considered to fill the soon-to-be open seat. Loeffler, a political outsider, submitted her application on Nov. 18, the last day to do so, in which she identified herself as a "lifelong Republican," and said she'll "stand with President Trump ... to Keep America Great."

"Politicians with radical agendas threaten to undermine and destroy all that has made this country the shining beacon of liberty and opportunity in the world," she wrote in her letter submitting an application.

If Loeffler runs in the special election next year to finish out the remainder of Isakson’s term, she could help regain support among suburban female voters who have drifted from the GOP in recent cycles, in part, due to the president's brashness.

Between 2011 and 2012, Loeffler, along with her husband Jeffrey Sprecher, the chairman and CEO of Intercontinental Exchange and the chairman of the New York Stock Exchange, made huge contributions to Restore our Future, Inc., a super PAC backing then-Republican candidate Mitt Romney’s presidential campaign. Loeffler donated $750,000 and Sprecher donated $780,000, according to Federal Election Commission filings.

More recently, in 2019, Loeffler and her husband each gave a $35,500 contribution per calendar year -- the maximum amount -- to the Republican National Committee, plus an additional $39,500 each to the RNC’s convention account, according to FEC filings.

ABC News' Kendall Karson contributed to this report.