Donald Trump, Bernie Sanders toss around possibility of debate

WASHINGTON – Chances are likely slim, but what about a Donald Trump-Bernie Sanders debate heading into the crucial June 7 California primary?

READ MORE: Donald Trump calls climate change a ‘hoax’, but is concerned it could ruin his golf course

That possibility surfaced Wednesday, even if in a jocular tone, in an indirect exchange between the Republican billionaire real estate mogul and the senator who Hillary Clinton hasn’t been able to bump from the Democratic presidential sweepstakes.

On ABC’s “Jimmy Kimmel Live,” Trump said he enjoyed watching Clinton’s increasingly heated sparring with Sanders.

WATCH: Trump would ‘absolutely’ approve Keystone XL pipeline

1:38 Trump would ‘absolutely’ approve Keystone XL pipeline

“I had no idea it was going to be so nasty,” said Trump, who said he’d be happy to engage Sanders in a one-on-one debate — as long as significant money goes to charity.

Sanders said on Twitter he’d welcome that. “Game on. I look forward to debating Donald Trump in California before the June 7 primary.”

WATCH: Donald Trump scores enough delegates to clinch GOP nomination. Jackson Proskow reports.

2:24 Donald Trump scores enough delegates to clinch GOP nomination