ABC, CBS and Fox News have expressed interest in hosting a debate between presidential candidates Donald Trump and Bernie Sanders.

Sources with knowledge of the situation told Variety that CBS News and Fox News have been in contact with the campaigns about a possible debate. A Fox News spokesperson confirmed that the network has been involved in talks. Meanwhile, a spokesperson for ABC News told Variety, “I can tell you we’re always interested in more opportunities to hear from the candidates.”

The idea of a debate between Trump, the presumptive Republican nominee, and Sanders, who trails frontrunner Hillary Clinton in the race for the Democratic nomination, emerged during Trump’s appearance Wednesday on “Jimmy Kimmel Live.” Kimmel allowed the Sanders campaign to plant a question in the interview, asking Trump whether he would be willing to debate Sanders before the June 7 California primary. Trump responded that he “would love to do that,” if the two candidates could use the event to raise money for charity.

Sanders later wrote on Twitter, “Game on. I look forward to debating Donald Trump in California before the June 7 primary.”

Speaking at a press conference Thursday morning, Trump said that his campaign had already fielded calls from several networks about the possibility of hosting a debate. He added, “I’d love to debate Bernie. He’s a dream.”

Trump has said that he would hope to raise $10-15 million for an unnamed charity from a debate.

An NBC News spokesperson declined to comment when asked whether that organization had been in talks the campaigns regarding a debate. A CNN spokesperson did not respond immediately to a request for comment.

Fox News originally floated the idea of a Trump-sanders debate in March. The New York Times reported at the time that the cable network had nearly drawn the two candidates together for what ended up being a town-hall event with Sanders and Clinton moderated by Bret Baier.