“Iron Mike” Tyson endorsed the upstate Republican looking to replace Rep. Elise Stefanik announced in a move the candidate hopes will help him KO Democrats eyeing a November upset.

GOP candidate and former boxer Anthony Constantino touted the endorsement of “Iron Mike,” the former champion who grew up in Catskill, New York.

“I’m honored to be endorsed by an Upstate Legend and American Icon, the one and only, Iron Mike Tyson,” Anthony Constantino wrote in a an announcement Monday.

Constantino had started professionally boxing at 40 and went 2-1 with two knockouts while building his Sticker Mule firm into a 1,000-person manufacturing operation.

The two connected Friday after Tyson flew with President Trump aboard Air Force One to his rally in Syracuse. Tyson told Constantino that he looked “good on TV” during his roughly 16-minute address Friday, according to his campaign.

“President Trump brought a legend here, one of my personal heroes, Mike Tyson,” Constantino said before leading the crowd in a “Thank You Iron Mike Tyson” chant Friday. “I want to say we should all feel honored to have Mike Tyson with us.”

Tyson told the crowd he was happy to be on stage with Trump.

“ And there’s no way in the world I would ever be here if it wasn’t for a president like Donald Trump,” Tyson said.

The champ, who was born in Brooklyn before he spent his formative years in Catskill, became the youngest ever heavyweight boxing champion at the age of 20. In 1992, he was convicted of raping a 20-year old Miss Black America contestant and sentenced to six years in prison.

The 21st Congressional District is right-leaning turf but Democrats are hoping for a heavyweight battle to flip it blue.

The expansive district stretches from the St. Lawrence Seaway and outskirts of Fort Drum near Watertown east across the Adirondacks to Plattsburgh and down to Saratoga County.

Trump easily carried the 21st District 60% to Kamala Harris’ 39% – a massive 21% margin.

But a recent poll Siena University poll suggested a Democratic midterm wave next month could wash all the way up to the North Country. Democrat farmer Blake Gendebien holds a 4-point lead over Constantino — 46% to 42%.

The poll has a 4.6% margin of error.

A majority of respondents – 52% – rated Constantino unfavorably, compared with 39% favorable.

Even Trump’s favorability is slightly underwater according to the NY21 Siena Poll – 46% favorable, 52% unfavorable.

Of the 496 respondents Siena surveyed, 54% said they believe their member of Congress should be a “check on Trump” versus 41% who say they should support the president’s agenda.

Constantino’s campaign dismissed the survey as a “scam poll.”

“Anthony Constantino is winning NY-21 despite everyone in the media trying to prevent that at all costs,” Alex DeGrasse, a former Stefanik aide now working for Constantino’s campaign, said in a statement last week.

Constantino emerged victorious from a bitter primary against Assemblyman Robert Smullen (R-Montgomery), who’d been backed by state GOP Chairman Ed Cox and 12 of the 15 county Republican committees in the district. Trump jumped into the race, throwing his support behind Constantino.

Constantino’s eccentric pro-Trump attitude and backstory as an outsider have attracted attention.

After he first announced his intention to run for Stefanik’s seat when she was preparing to be tapped to be U.N. ambassador before Trump pulled the nomination, Jerry Kassar sued him for defamation after Constantino claimed the state Conservative Party Chairman threatened to kill him.

He later relaunched his current campaign in front of a wall made of turkeys that he was handing out to supporters outside his Amsterdam facility where he installed a 100-foot “Vote for Trump” sign in 2024.

It was revealed this summer that one of his staffers had been charged with stabbing a man to death in Nevada in 2023.

Democrats also recently added Gendebien to their “Red to Blue” program, indicating they may be eyeing a potential upset in the seat, though it’s unclear if Dems will funnel cash into the race.

“Anthony Constantino can tout all the celebrity muscle he wants, but standing next to a fighter doesn’t make you one,” Gendebien saod in a statement to The Post.

“Voters will be in my corner on Election Day because they see right through Constantino — a featherweight who will do whatever Washington tells him” he said punching back.

New York Democratic Committee Chair Jay Jacobs bashed Constantino’s Tyson endorsement. 

“I didn’t know Mike Tyson to be the sharpest tool in the box,” Jacobs told The Post.

“He’s taking the endorsement from Mike Tyson because he can’t get an endorsement from anyone credible — except Donald Trump,” he claimed.

“I don’t think voters in the North Country are going to bed asking, `Who is Mike Tyson voting for?’” the Long Island-based Dem said.

The National Boxing Hall of Fame is located in Madison County in the neighboring 22nd congressional district. Tyson was inducted there in 2011.