Oprah Winfrey made her 2018 midterm campaign debut on Thursday, hitting the stump for Democrat Stacey Abrams in Georgia’s heated gubernatorial contest – the latest celebrity or political heavyweight bringing their star power to the final stretch going into Election Day.

To thunderous cheers redolent of those from her famously effusive studio audiences, Winfrey took the stage in Marietta, Ga., to back Abrams as the candidate who “cares about the things that matter” – ticking off her stances on Medicaid expansion, environmental protection and “common-sense gun control.”

“I don’t want to run. I’m not trying to test any waters,” she insisted, taking care to blunt any potential headlines on presidential ambitions (she claims to have none). “I’m here today because of Stacey Abrams.”

In striking terms, Winfrey urged Georgians to exercise their right to vote: “I’m here today because of the men and because of the women who were lynched, who were humiliated, who were discriminated against, who were suppressed … for the right, for equality at the polls. … I refuse to let their sacrifices be in vain.”

The media mogul and the gubernatorial nominee later embraced as Winfrey turned over the microphone to the candidate.

The appearance is one of many aimed at turning up turnout going into Election Day. Abrams, who would be the first black female governor of any state, has generated a particular amount of star power in her race against Republican Brian Kemp.

Comedian Will Ferrell also swung into Georgia this week to boost Abrams’ candidacy.

President Trump and former President Barack Obama, too, are planning to hit Georgia, to support their respective parties’ nominees. And while Winfrey was campaigning for Abrams on Thursday, Vice President Pence was hitting the stump for Kemp.

The blitz underscores the high stakes in one of the defining contests of next week’s midterms, as Abrams vies to make history while Kemp tries to maintain the GOP’s dominance in a state Democrats believe is on the cusp of becoming a presidential battleground.

Trump’s scheduled appearance Sunday sidelined the last debate scheduled between Kemp and Abrams. Atlanta’s WSB-TV confirmed late Wednesday that a long-planned matchup at 5 p.m. Sunday had been canceled and would not be rescheduled before polls open Tuesday.

Obama will appear with Abrams on Friday at a cluster of historically black colleges near downtown Atlanta.

Multiple polls show a statistical dead heat between Kemp and Abrams.

Fox News’ Power Rankings rates the race as a toss-up.

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Both candidates have run consistent appeals to their respective bases. Kemp has embraced Trump and echoed the president’s hard-line policies on immigration, and he’s focused much of his campaigning in the state’s more conservative pockets beyond metro Atlanta.

Meanwhile, former President Jimmy Carter, an Abrams supporter and former Georgia governor, garnered significant attention this week with a personal plea that Kemp resign as secretary of state, Georgia’s chief elections official, to ensure public confidence in the results of what’s expected to be a close race.

Comedian Dave Chappelle also has made waves by campaigning for his longtime friend Ben Jealous, the former NAACP leader now running for governor in Maryland. Jealous trails in the race against GOP Gov. Larry Hogan, but Chappelle tried to boost the Democratic nominee at a University of Maryland event earlier this month.

Trump and Obama, meanwhile, are both going on a spree of campaign appearances across the country.

The sitting president will be in Missouri Thursday evening, where Republican Josh Hawley is facing Democratic Sen. Claire McCaskill in one of the season’s tightest Senate contests.

Trump later heads to West Virginia and Indiana, while Obama heads to Georgia and Florida, where he’ll boost Sen. Bill Nelson and Tallahassee mayor Andrew Gillum, who is running for governor.

On Sunday, the former president will be in Gary, Indiana, for Sen. Joe Donnelly, who is among the most endangered Senate Democrats, and in his hometown of Chicago for J.B. Pritzker, who is the favorite in Illinois’ race for governor.

The Associated Press contributed to this report.