On the eve of the contentious Republican senatorial primary vote in Pennsylvania, Fox News star Sean Hannity intervened… and not everyone is happy with the conservative commentator.

Hannity has backed Mehmet Oz, known as television personality “Dr. Oz”, who has divided so-called “MAGA Republicans” — conservatives who are typically in lockstep with former President Donald Trump, who also has endorsed Oz.

Some are suspicious of the ideological leanings of the celebrity heart surgeon who gained fame as a frequent guest on Oprah Winfrey’s talk show, but has been attacked by millions of dollars of TV ads from another rival, former hedge fund CEO David McCormick.

That’s benefited Kathy Barnette, a conservative commentator who faced little scrutiny for most of the campaign before resonating in the final stretch with a fierce message opposing abortion in all circumstances.

Barnette has surged and is within the margin of error with Oz, according to the latest Trafalgar poll —

Final #PASen @trafalgar_group
#GOP primary #poll (5/14-16) it's coming down to the wire – within 2%. #PApol

28.5% @DrOz
26.8% @Kathy4Truth
21.6% @DaveMcCormickPA
7.1% @CarlaHSands
6.7% @Jeff_Bartos
2.1% @BochettoForPA
1.7% Sean Gale
5.5% Und
See report: https://t.co/zxG42J4Jht pic.twitter.com/1p1qmX2rNz

— Robert C. Cahaly (@RobertCahaly) May 17, 2022

Trump, who has held campaign-style rallies with Oz, insists he is the best candidate to keep the Senate seat in Republican hands this fall.

Given his level of involvement in the race — including a virtual event on Oz’s behalf late Monday — a loss would be a notable setback for the former president, who is wielding endorsements as a way to prove his dominance over the GOP ahead of a potential 2024 presidential run.

Hannity also threw his weight into the race, attacking the conservative Barnette just one day before the primary — a stunning move for the Fox News personality who risks alienating a portion of his audience.

Hannity attacked Barnette for being at the infamous Jan. 6 rally in support of Trump. She was seen on camera marching with a far-right group called the “Proud Boys” — which Hannity attacked.

“Look at your screen. Here is Barnette marching alongside — this just broke today — radical ‘Proud Boys’ during Jan. 6th,” Hannity told viewers.

“She said she had no idea who they were, and that she didn’t breach the Capitol,

pic.twitter.com/BpiKPvg6ME

— Eli Stein (@Fight_Back_NYC) May 17, 2022

Hannity also blasted Barnette for a number of controversial tweets from years ago.

He warned viewers that this “will all come up in a general election.”

Hannity going after Barnette for her tweets again pic.twitter.com/aDMYIcpKVU

— Acyn (@Acyn) May 17, 2022

Conservative commentators on social media shot back, attacking Hannity for his defense of Oz.

https://twitter.com/Bubblebathgirl/status/1524792858498277376

https://twitter.com/LATiffani1/status/1524921432244768768

Video: Sean Hannity gets unlikely Democratic ally

The Horn editorial team and the Associated Press contributed to this article