Andrew Yang's promised "big" surprise at Thursday night's debate could be huge for 10 families.

The entrepreneur — who'd vowed to do something never before seen on a debate stage — went full Oprah, promising to pay $1,000 a month to 10 random American families for a year.

"I’m going to do something unprecedented tonight,” Yang said. “My campaign is now going to give a Freedom Dividend of $1,000 a month to 10 American families for an entire year, someone watching this at home right now.”

The recipient will be chosen in an online raffle.

"It's original. I'll give you that," said the next candidate to speak after Yang's opening statement, South Bend, Indiana Mayor Pete Buttigieg.

"Freedom dividends" are the linchpin of Yang's surprising campaign — he's proposing that the government should pay every American over the age of 18 a no-string-attached $1,000 a month.

Yang has been paying the dividend out of his own pocket to three families — one in New Hampshire, one in Iowa and one in Florida. His campaignsaid the new payments would come from his campaign funds.

“The campaign is excited to work together with our supporters to help create more stories about what the Freedom Dividend means for American families. It will enable and empower citizens to pay their bills, switch jobs, take care of loved ones, and plan for the future,” said campaign manager Zach Graumann.

As inventive as the pitch may be, it’s not clear the raffle is legal under campaign finance law. Campaign funds can’t be used to pay for any expenses to “fulfill a commitment, obligation or expense of any person that would exist irrespective of the candidate’s campaign or responsibilities as a federal officeholder,” according to the Federal Election Commission.

Yang’s campaign could argue that this passes legal muster because the raffle is a part of his campaign. And the campaign said in a statement that its lawyers have declared the raffle “fully compliant with all FEC regulations.”

But some campaign finance experts have thrown cold water on that reading. “If it’s just given for no work done, for nothing at all, just a gift, that is inappropriate,” Ann Ravel, a former Federal Election Commission chief, told Time. “You can’t just give cash.”

Election law expert Rick Hasen had a different take. "I don’t see a legal problem so long as it is not tied to voting or registering," he tweeted.

Yang had been teasing the announcement in recent days, tweeting on Tuesday that he had "something big in store" for the Houston debate.

He then made several jokes about what that would be.

"For those wondering, I will be crowdsurfing in sandals at Thursday's debate," he tweeted on Wednesday.