Jerry Seinfield sharply disputes Donald Trump's unsubstantiated birther claims. (NYI Collage)

Jerry Seinfield sharply disputes Donald Trump’s unsubstantiated birther claims. (NYI Collage)

Donald Trump is embroiled in another of his famous feuds, this time, with comedian Jerry Seinfeld. The Donald’s birther rants prompted Seinfeld to cancel an appearance at son Eric Trump’s upcoming charity event.

Trump, who is sounding out a run for president in 2012, enraged both Democrats and Republicans by resurrecting charges that President Barak Obama was not born in the United States.

That would make him ineligible to serve as president, if true. The claims have been widely refuted, but Trump began trumpeting the issue again to win the sympathy of far right-wingers.

In response, Seinfeld, 56, said he will not attend the St Jude Children’s Research Hospital benefit because of Trump’s demagoguery.

“I just learned you cancelled a show for my son’s charity because of the fact that I am being very aggressive with respect to President Obama, who is doing an absolutely terrible job as our leader,” Trump wrote in a letter to Seinfeld, according to the New York Post.

“What I do feel badly about,” he wrote, “is that I agreed to do, and did, your failed show ‘The Marriage Ref,’ even though I thought it was absolutely terrible,” Trump continued.

“Despite its poor ratings, I didn’t cancel on you like you cancelled on my son and St Jude. I only wish I did,” he added in a fit if pique.

A rep said Seinfeld had become “increasingly uncomfortable,” with Trump’s grandstanding.

“Jerry feels this kind of demagoguery has no place in public discourse,” the rep told The Post.

“He has respectfully withdrawn from the event, and is making a contribution both to the Eric Trump Foundation and to St Jude.”

Trump has gained ground with his birther campaign. He tied with Arkansas Gov. Mike Huckabee with 19 percent of the potential vote in the Republican presidential race.