Former White House chief strategist Stephen K. Bannon has weighed in on who could be President Trump’s toughest challenger in 2020 — and it’s not Joe Biden, Bernie Sanders, Elizabeth Warren or any of the other scores of Democratic politicians positioning themselves for potential bids.

The biggest foe, Bannon says, would be Oprah Winfrey.

“I think we’re in a different era,” Bannon said during an interview Wednesday night on CNBC. “I think we’re in an era that media and understanding media and understanding how to communicate on a mass basis to the American people is so much more important than being in a state legislature.”

Bannon said he remains confident that Trump will be reelected. But he also floated other possible 2020 contenders who do no come from politics, including actor Dwayne Johnson, known as the Rock, and businessman and reality star Mark Cuban.

“Don’t dismiss people today that are either executives that understand media or people that are media types,” Bannon told host Michelle Caruso-Cabrera. “Do not think that those people can’t somehow start to get traction, more so than some guys in the U.S. Senate.”

Speculation about a Winfrey challenge to Trump surged in January after she delivered a rousing speech at the Golden Globes awards ceremony, saying that “a new day is on the horizon.”

Winfrey, a cultural icon, has talked down the possibility since. In a recent interview with British Vogue, she said that going through the process “would kill me.”

Bannon had expressed his admiration for Winfrey before.

In the book “Devil’s Bargain,” journalist Josh Green reported that Bannon considers Winfrey to be an “existential threat” to Trump’s presidency if she campaigns for Democrats in this year’s congressional elections. The risk in Bannon's mind, according to the book, is that Democrats could take control of the House and impeach Trump.