Hillary Clinton told supporters at a Hamptons fundraiser Monday that she was unsure “which Donald Trump will show up” on the debate stage when both rivals face-off for the first time at Hofstra University next month.

“This is the most unpredictable election season that I certainly can remember,” Clinton told about 20 supporters at a Monday afternoon fundraiser held at the East Hampton home of software developer Charles Phillips, and his wife Karen. “I’m running against someone who will say or do anything, and who knows what that may be.”

The event was part of a three-day Clinton campaign fundraising blitz on Long Island’s East End that started Sunday with a $33,400-a-head garden party in Sag Harbor, and will cap-off Tuesday with a reception hosted by singers Jimmy Buffett and Jon Bon Jovi.

Clinton asked those at the $33,400-a-head Wainscott fundraiser, to share their opinion on how she “should debate” the Republican presidential candidate when they square-off on Sept. 26.

“I do not know which Donald Trump will show up,” Clinton said. “Maybe he’ll try to be presidential . . . or maybe he’ll try to come in and try to . . . score some points.”

Trump’s campaign did not immediately respond to an email seeking comment, but his campaign has previously said he began prepping for the debate earlier this month.

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Sources familiar with Clinton’s campaign schedule said she will have headlined at-least six events by the end of the three-day fundraising spree.

The Democratic presidential nominee has so far amassed more than $11 million in campaign contributions from three events held Monday and Sunday — including $6 million raised at a 100-person fundraiser held Sunday by New York Giants co-owner Jonathan Tisch, according to CNN.

“The buzz is all over town that the Clintons are here, and everyone wants to see the Clintons,” said Barbara Layton, owner of Babette’s, an East Hampton eatery frequented by the Clinton family.

Layton, a Clinton supporter who attended a jazz reception that drew 200 supporters Sunday night, said several of the fundraising events sold out weeks ago.

“The Hamptons are always eager to support the Clintons,” Layton said.

Entry into the Buffett and Bon Jovi “dinner and dancing” event, to be held at Buffett’s North Haven estate, starts at $10,000 per person, but guests could opt to pay $100,000 for “premium seating” and the chance to attend a private reception with Clinton.

Also planned for Tuesday is a cocktail reception in Sagaponack, with admission ranging in price from $33,000 to $100,000.

Last month, Clinton received $90 million in campaign contributions, while Trump reported an $80 million fundraising haul.

Clinton has outpaced Trump in statewide and Long Island fundraising, according to federal campaign finance reports. Clinton raised $17.8 million throughout the state in July, including $353,800 from supporters on Long Island. Meanwhile, Trump raised $751,189 statewide and $209,452 on Long Island.

Clinton also attended cocktail receptions and dinners in Bridgehampton, East Hampton, and Quogue with entry ranging in price from $1,000 to $33,400 per person.

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Trump also headlined a pricey Hamptons fundraiser on Aug. 13. New York Jets owner Woody Johnson hosted an event at his East Hampton home with tickets ranging in price from $10,000 to $20,000, according to social media postings from supporters who attended the event.