WASHINGTON — Gaffe-prone former veep Joe Biden put his foot in it again on Monday — claiming to have worked on the 2016 Paris Climate Accord with a Chinese leader who died 19 years earlier.

During a campaign stop in South Carolina ahead of the state’s primary on Saturday, Biden told a crowd his experience on the world stage as vice president under Barack Obama made him the right person to defeat President Trump.

“One of the things I’m proudest of is getting passed, getting moved, getting in control of the Paris Climate Accord,” Biden told the crowd in a video circulating on Twitter.

“I’m the guy who came back after meeting with Deng Xiaoping and making the case that I believe China will join if we put pressure on them. We got almost 200 nations to join,” he said.

Only problem is Deng Xiaoping, China’s former paramount leader, died in 1997.

It’s unclear if Biden was referring to China’s current President Xi Jinping, who took power in 2013 and oversaw China’s involvement in the 2016 climate deal.

The presidential wannabe has been plagued by constant word salad on the campaign trail — on Monday night telling South Carolina voters that he was running for the United States Senate.

The 77-year-old, whose White House bid is now on life support, is also under fire for claims he was arrested while trying to see Nelson Mandela in South Africa.

Over the past two weeks, Biden has repeatedly claimed he was cuffed in Soweto with the US ambassador for trying to visit Mandela at Robben Island Prison in the 1970s.

But Andrew Young, the former US ambassador to the UN who traveled with Biden to South Africa, denied that ever happened.

“No, I was never arrested and I don’t think he was, either,” Young, 85, told the New York Times.

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Biden is pinning his presidential hopes on black voters in the Palmetto State, long considered his campaign’s firewall, after disastrous showings in Iowa and New Hampshire.

But new polls show Biden’s huge lead has vanished and he is locked in a tight race with Vermont socialist Sen. Bernie Sanders.