Former President Barack Obama said during a just-released interview that people who watch Fox News are living on a "different planet" than those who listen to National Public Radio (NPR).

Obama joined David Letterman in the first episode of the former late-night host's new Netflix show "My Next Guest Needs No Introduction." In the interview, which was released Friday but recorded in the fall, Obama talked about his personal life as well recent political and social issues.

Letterman asked the former president about "hypothetical" situations in the United States, asking which circumstance would be most damaging to democracy.

"Let's just say there is a democracy, and the voting process is being monkeyed with by foreign countries," Letterman said. "Hypothetically, what is more damaging to that democracy? Would it be the diminishment, by the head of the democracy, of [the] press, or would it be somebody screwing around with the actually voting process."

Obama refrained from giving a direct answer and avoided referring to President Donal Trump despite Letterman's thinly-veiled references to the president's complaints of "fake news" and to Russian meddling in the 2016 election.

"One of the biggest challenges we have in our democracy is the degree to which we don't share a common baseline of fact," Obama said.

The former president then described the partisan divide as it relates to media consumption in the United States, and how Russia exploited the differences during the 2016 election. He described the divide by saying Americans are "operating in completely different universes," and went as far to say Fox News viewers are living on a "different planet" than NPR listeners.

"What the Russians exploited, but it was already here, is we are operating in completely different information universes," Obama said. "If you watch Fox News, you are living on a different planet than if you listen to NPR."

While Fox News is more often viewed by Republican or right-leaning viewers, NPR is widely recognized as "radio by and for liberals," and itself has admitted a liberal bias. Media Research Center points out the organization's bias, quoting a Washington Post reporter who described the media landscape as varying from "those who cheer Fox to those who swear by NPR."

As special counsel Robert Mueller's investigation has been ongoing, news anchors at MSNBC and CNN have claimed there has been a "coordinated effort" with Fox News to push a message that benefits the president's agenda.

NPR reports to have 36.8 million total weekly listeners for all NPR stations; Fox News routinely competes for the number one spot in cable news ratings every month.