Trump and Sanders have gone through a series of debates against rivals within their parties, but Republican and Democratic candidates traditionally do not debate each other until the parties have selected their respective nominees.
Republican Donald Trump and Democrat Bernie Sanders could be heading to an unconventional face-off in California, after the two presidential candidates expressed an interest in squaring off in a one-on-one debate.
That would leave Democratic front-runner Hillary Clinton on the sidelines in another bizarre twist to an unconventional election season.
Sanders, a US senator from Vermont, is still running behind Clinton in the battle for the Democratic presidential nomination. Trump reached the number of delegates needed to secure the party's presidential nomination on Thursday, the Associated Press reported on Thursday, citing its own delegate count.
In an appearance on ABC's "Jimmy Kimmel Live" late on Wednesday, Trump said he was willing to participate in a debate with Sanders.
"If I debated him, we would have such high ratings," the billionaire New York developer and former reality TV star said. "I think I should ... take that money and give it to some worthy charity."
Sanders appeared to agree in a post on Twitter on Thursday.
"Game on," he tweeted. "I look forward to debating Donald Trump in California before the June 7 primary."
Trump and Sanders have gone through a series of debates against rivals within their parties, but Republican and Democratic presidential candidates traditionally do not debate each other until the parties have selected their respective nominees.
The hashtag #BernieTrumpDebate began trending in the United States with news of the possible debate.
Trump spokeswoman Hope Hicks said in an email to Reuters on Thursday that there were no formal plans yet for such an event. Representatives for the Sanders campaign did not immediately respond to a request for comment.
Kimmel said he asked Trump about the debate at the suggestion of Sanders, who is scheduled to appear on the show Thursday night.
Sanders, a democratic socialist who was elected to Congress as an independent and has made economic equality a keystone of his campaign, has criticized Clinton for backing out of an agreement to debate before the California primary.
The Clinton campaign did not immediately respond to a request for comment on a possible Trump-Sanders debate.
Clinton has tried to woo Sanders supporters as she works to secure the party's nomination for the Nov. 8 election. But some worry that his supporters - who are largely young, working-class and disillusioned with the Democratic Party establishment - will turn instead to political neophyte Trump, who has championed a populist agenda.
Sanders has said he will do everything he can to ensure that Trump does not win the White House.