Iowa Gov. Kim Reynolds plans to give a blockbuster endorsement of Florida Gov. Ron DeSantis Monday, a source familiar told The Post.

Traditionally, Iowa governors stay neutral in the Iowa Caucus competition, but DeSantis has been courting Reynolds for months.

A Reynolds endorsement of DeSantis will also be significant because she will be bucking the party’s former presidential nominee. The DeSantis campaign teased an event with Reynolds in Des Moines on Monday.

“BIG NEWS! Gov. @KimReynoldsIA will be joining @RonDeSantis at his rally in Des Moines TOMORROW NIGHT!,” the campaign wrote.

Her imminent endorsement comes amid growing competition in the polls from former South Carolina and US ambassador to the UN Gov. Nikki Haley.

NBC News and the Des Moines Register first broke the news of Reynolds’ forthcoming endorsement.

Iowa is the first in the nation contest for the 2024 GOP nominating contest and will take place on Jan. 15 of next year.

Donald Trump’s allies have recently blanketed the airwaves with attack ads against the Sunshine State governor, though the former president is still the frontrunner in the Hawkeye State.

Trump is ahead of DeSantis by a whopping 31.5 percentage points, in the latest RealClearPolitics aggregate. DeSantis nabs 17.3% support on average while Haley rings in at 11.5%, per the aggregate.

Trump’s campaign quickly shrugged off news of the endorsement, pointing to a poll that concluded, “If either of the early state governors decided to back DeSantis, it would only shift the race a net 4 percentage points in his favor.”

“Kim Reynolds apparently has begun her retirement tour early as she clearly does not have any ambition for higher office,” the Trump campaign said.

“President Trump is the undisputed leader of the Republican Party and that’s why he not only leads every single Iowa poll by significant margins but also beats Crooked Joe Biden in the general.”

The 77-year-old former president had a friendly rapport with Reynolds during his presidency but previously chafed with her on the campaign trail.

“I opened up the Governor position for Kim Reynolds, & when she fell behind, I ENDORSED her, did big Rallies, & she won. Now, she wants to remain ‘NEUTRAL.’ I don’t invite her to events! DeSanctus down 45 points!” Trump wrote on Truth Social back in July.

His jab at Reynolds at the time came in response to a report from the New York Times about her warming up to DeSantis.

Reynolds has attended a melange of different Republican contenders, but previously suggested she would likely stay neutral.

“I’m not going to tell Iowans what to do,” she said at one point.

Trump lost Iowa to Sen. Ted Cruz (R-Tx.) during the 2016 election cycle, but managed to cruise to the GOP nomination anyways.

The Post contacted Reynolds’ office for comment.

Later this week, DeSantis will join his fellow Republicans on the GOP debate stage in Florida for the third verbal rumble of the cycle.

Trump appears set to skip the verbal bout and hold a rally nearby instead.