Well-known celebrity physician Mehmet Oz on Tuesday declared his candidacy for the Senate in Pennsylvania, joining a competitive Republican primary field in the crucial battleground state.

The announcement by the 61-year old Oz – a cardiac surgeon, author and host of TV’s "Dr. Oz Show" – was widely expected as he’s already been assembling a campaign staff in the 2022 race to succeed retiring GOP Sen. Pat Toomey. The high-profile Senate contest could ultimately decide if the Democrats hold on to their razor-thin majority in the chamber.

"Pennsylvania needs a conservative who will put America first, one who can reignite our divine spark, bravely fight for freedom, and tell it like it is. That's why I'm running for Senate," Oz said in a statement announcing his candidacy.

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Oz will sit down for his first national interview as a Senate candidate on Tuesday evening on Fox News’ "Hannity." Host Sean Hannity teased Oz's appearance at the end of his Monday night program, saying that he had a "huge announcement" and hinted "think midterm election."

Oz enters the GOP Senate primary with sizable name recognition – thanks to his long-running TV show. Oz grabbed national attention more than a decade ago when Oprah Winfrey introduced him to her program’s massive audience. He would also be able to self-fund his Senate bid by dipping into his estimated net worth of roughly $100 million.

The candidate has lived for years in New Jersey, but Oz registered to vote as a Republican last December in Pennsylvania’s Montgomery County, using the home of his wife’s parents in the affluent Philadelphia suburb of Bryn Athyn as his residence. According to election records, he’s voted twice by absentee ballot in Pennsylvania this year. Oz previously lived in the Keystone State decades ago, as he graduated from the University of Pennsylvania’s medical school and Wharton business school in 1986.

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Oz is a political outsider and first-time candidate, and he will face scrutiny as little is known about his political beliefs. And also he’s sure to face serious questions over his sometimes controversial medical advice. He's been criticized by his peers for promoting diet pills that other doctors have slammed as a sham.

Last year, during numerous appearances on the Fox News Channel amid the coronavirus pandemic, he promoted the use of hydroxychloroquine to treat against COVID-19.

In his announcement, Oz argued that "COVID has shown us that our system is broken. We lost too many lives, too many jobs, and too many opportunities because Washington got it wrong. They took away our freedom without making us safer and tried to kill our spirit and our dignity. As a heart surgeon, I know how precious life is."

Oz launches Senate campaign

Well-known celebrity physician Mehmet Oz announced his candidacy for the Senate in Pennsylvania on Nov. 30, 2021. Oz is seen in a January 2020 appearance on the Fox News Channel. (Fox News)

The GOP Senate race in Pennsylvania was rocked a week ago when former congressional candidate Sean Parnell, the perceived front-runner in the Republican field, who enjoyethe backing of former President Donald Trump, suspended his campaign hours after he lost a bitter fight for custody of his three children to his estranged wife.

Among the current leading contenders in the field of nearly 10 GOP candidates are Jeff Bartos, a real estate developer and longtime GOP fundraiser who was a 2018 candidate for lieutenant governor, and Carla Sands, a business executive and Republican donor who served as U.S. ambassador to Denmark during the Trump administration.

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David McCormick, a hedge fund executive, West Point graduate, Gulf War combat veteran, and former Treasury Department official in former President George W. Bush’s administration is seriously mulling a bid of his own. The Pittsburgh native is married to Dina Powell McCormick, a Wall Street executive who served as a deputy national security adviser in the Trump administration.

Also considering Republican Senate runs are former Rep. Ryan Costello, who served two terms representing a district in Philadelphia’s suburbs before deciding against running for reelection in 2018, and former Rep. Keith Rothfus, who represented Pennsylvania’s 12th Congressional District from 2013 to 2019. After the state Supreme Court released new district maps in early 2018, Rothfus ran for reelection in the Pennsylvania's 17th Congressional District, losing to Democrat Conor Lamb, who’s now running for his party’s Senate nomination.

After Parnell’s departure from the race, Trump made it clear that he’ll likely weigh in again in Pennsylvania’s Republican Senate primary.

"#PASen remains a top priority for Pres. Trump & the ‘22 MAGA Map—rallying our movement behind the best America 1st candidate remains critical," Trump spokesman Taylor Budowich tweeted last week.

U.S. President Donald Trump thumbs up to the media after speaking about the impeachment hearings on the the South Lawn of the White House in Washington before his departure to Austin, Texas on November 20, 2019. Photo by Yuri Gripas/ABACAPRESS.COMNo Use France Digital. No Use France Print.

Oz has a connection to Trump, as the then president named him to the Presidential Council on Sports in 2018 and last December reappointed Oz for a second two-year term.

The Democratic Senatorial Campaign Committee (DSCC) argued that "Oz’s campaign announcement demonstrates the chaos which is engulfing Pennsylvania’s GOP Senate primary."

"The influx of unqualified, untested and wealthy Republican candidates in this race will intensify the viciousness of their intra-party fight and leave their ultimate nominee badly out of step with Pennsylvania's general election voters. The GOP will find Oz is no miracle cure for their mounting problems in this primary," DSCC spokesperson Patrick Burgwinkle charged.

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Seven Democrats are running for their party’s Senate nomination in Pennsylvania, including Lt. Gov. John Fetterman and Rep. Conor Lamb.

Fox News' Andrew Murray contributed to this report