Klein, who lived in Manhattan his entire life, was 85. Klein caught the coronavirus in a nursing home, though originally it was deemed just pneumonia, his wife said.

Long before there was Spike Lee, Klein was known to associates as the “Knicks SuperFan.”

Klein also was a former co-owner of the Carnegie Deli and grew close to Knicks legend and MSG Network analyst Walt Frazier, helping him launch his restaurant “Clyde’s Wine and Dine.”

Though he was too ill to use his tickets the last couple of seasons, Klein, who had Alzheimer’s, diligently watched every Knicks game on television until this season, his wife said.

In prior interviews with The Post, Klein defended embattled owner James Dolan, feeling he got a bad rap and cared deeply about the longtime season-ticket holders.

Dolan also tested positive for coronavirus. There has been no update on Dolan’s condition since March 28, when he was reporting “little to no symptoms” and was self-isolating in the Hamptons.