The robocall, reportedly from white supremacist group The Road to Power, impersonates Winfrey using racist language in a mock endorsement for Abrams, who is African-American. A lawyer and former minority leader of the state's House of Representatives, Abrams is also the first black female gubernatorial nominee for a major political party in U.S. history.
Both Abrams and her Republican opponent, Secretary of State Brian Kemp, condemned the robocall.
"This automated call is absolutely disgusting," Kemp said in a statement Friday. "I stand against any person or organization that peddles this type of unbridled hate and unapologetic bigotry. These vile efforts to degrade and disparage others are contrary to the highest ideals of our state and country. We unequivocally condemn this group and their horrible actions."
Abrams' campaign went on the attack against Kemp. "It's disturbing that after months of racist, sexist and inaccurate attacks against Stacey Abrams, Brian Kemp has only now suddenly decided to find a conscience as polls are tightening and Georgia voters are making it clear that they reject the kind of hate he and his allies have been spewing around the state," the Abrams campaign statement said.
Winfrey strongly endorsed Abrams and stumped for her at a campaign event Thursday in Marietta. At the event, Winfrey, who briefly drew national attention as a possible challenger in 2020 to President Donald Trump, said she was a registered Independent and that she was "not trying to test any waters" for a political run.
"I've earned the right to do what I want to do when I want to do it. I've earned the right to think for myself — and to vote for myself," Winfrey said to rousing applause in her speech.
Soon after, the talk show host and media mogul posted Instagram videos of her canvassing door-to-door for Abrams.
Abrams has long criticized Kemp, who is also in charge of overseeing the state's elections, of using selective voter suppression tactics to stifle Democratic turnout. Kemp has denied using such tactics, saying "the liberal left" makes the same allegations against Republicans "every two years."
Over the weekend, Kemp's office reported a potential cybersecurity breach on Georgia's "My Voter Page," and said it had "opened an investigation into the Democratic Party of Georgia."
Abrams called the announcement "desperate." The state's Democratic Party said the allegations are "100 percent false."