Kimmel, who said he was relaying a question from Sanders, asked Trump during his segment on the late-night ABC show if he’d be willing to debate the Vermont Senator before the California primary on June 7.

“Yes, I am. How much is he going to pay me?” Trump said.

Earlier this week, Sanders’ primary opponent Hillary Clinton declined an invitation to debate Sanders on Fox News before the California contest. Trump, meanwhile, said he would face off against Sanders, if the debate benefited a good cause: “If I debated him, we would have such high ratings, and I think I should take that money and give it to some worthy charity.” Trump, who has all but locked up the Republican nomination, said he’d also be fine with a network fronting the money.

[youtube https://www.youtube.com/watch?v=vzO-JYjEcHE]

It’s not entirely clear if Trump was sincere in agreeing to a debate, but Sanders’ campaign seemed to take his remarks as genuine. Early Thursday morning, Sanders sent a tweet acknowledging Trump’s acceptance of the invitation.

Game on. I look forward to debating Donald Trump in California before the June 7 primary.

— Bernie Sanders (@BernieSanders) May 26, 2016

When asked for further comment on Trump’s remarks and if a debate was in the works, Trump spokesperson Hope Hicks told Fortune she had “nothing new to add.” Sanders’ campaign did not immediately responded to Fortune’s request for comment.

Sanders is set to appear on Jimmy Kimmel on Thursday night and will no doubt be asked about the theoretical debate.

Apart from the debate speculation, Trump’s appearance on Kimmel sparked other headlines for prompting two acts—R&B singer Weeknd and rapper Belly—to back out of a scheduled segment on the show because the episode would also feature the Republican candidate. The two musicians—both from Canada—were set to perform “Might Not,” a song by Belly that features the Weeknd.

Belly said he canceled the appearance because he didn’t want to share the same stage as Trump since he disagrees with the billionaire businessman’s views and beliefs. “I just didn’t want to feel like I was a part of a celebration for somebody who has beliefs that majority of us don’t agree with,” he said in a statement.