Bill Maher just messed up.

On his HBO program Real Time Friday night, which tapes live, the comedian dropped the N-word during a sit-down interview with Sen. Ben Sasse (R-Nebraska), who has received praise for his #NeverTrump stance.

After some polite back and forth between Maher and the Republican senator, who both seemed to agree on the subject of the latter’s recent book—about how “spoiled and entitled” millennial kids are, obviously—the following exchange happened.

“Halloween used to be a kid thing,” Maher remarked.

“It’s not anymore?” said Sen. Sasse.

“Not out here,” explained Maher. “No, adults dress up for Halloween. They don’t do that in Nebraska?”

“It’s frowned upon. Yeah, we don’t do that quite as much,” he replied.

“I’ve gotta get to Nebraska more,” offered Maher.

“You’re welcome. We’d love to have you work in the fields with us,” joked Sen. Sasse.

Then it happened: “Work in the fields? Senator, I’m a house nigga.”

Maher’s terrible, off-color—and frankly, more than a little racist—joke received a mixture of groans and laughter from the audience. Sen. Sasse was pretty firmly in the laugh camp, red-faced and grinning (albeit nervously) from ear-to-ear. Why the senator chose to play along instead of correcting Maher or saying anything is anyone’s guess.

To the groaners in the crowd, Maher asserted, “It’s a joke.”

But that excuse isn’t nearly good enough. Twitter, understandably, came after the comedian for using the N-word—a term of racial subjugation and oppression that is never OK for white people to use, in any context.

Maher’s made several controversial statements of late, from cracking an Ivanka Trump incest joke to agreeing with much of what transphobic guest Milo Yiannopoulos had to say on his program—which served as yet another example of the comic’s troubling views on the trans community.

This one will surely earn Maher widespread condemnation, although it remains to be seen if the famously unapologetic comedian will be the bigger man and apologize.