“The Tonight Show” host Jimmy Fallon and Mayor Rahm Emanuel at the Polar Plunge. | Sun-Times/Lori Rackl

Jimmy Fallon jumped into cold Lake Michigan for Mayor Rahm Emanuel.

Now it’s time for the mayor to sit in the hot seat for Fallon.

Emanuel is scheduled to be a guest on “The Tonight Show” June 3.

“We’ll write some thank you notes together,” Emanuel joked about his upcoming appearance on television’s top-rated late-night talk show.

This isn’t just another celebrity booking lined up by Emanuel’s Hollywood super agent brother, Ari.

“We cut the middle man out,” Rahm said. “We didn’t want to give anybody 10 percent.”

The mayor is going on the show to live up to his end of a bargain struck shortly after Fallon took over the NBC chatfest in February.

It all started when a Sun-Times article quoted Fallon saying he was “scared of” Emanuel, and the mayor had an open invitation to be a “Tonight Show” guest — or host, for that matter.

“It was clearly a joke but I decided let’s use it, man,” Emanuel said.

The mayor taunted the rookie “Tonight” host on Twitter, tweeting that he’d accept Fallon’s offer to be on the show — if the former “Saturday Night Live” star would join him for the Polar Plunge.

Fallon took the bait, although the bone-chilling experience on that 10-degree day in March looked like it sucked the life out of him.

Makes you wonder if the late-night host has any payback planned when Emanuel drops by Studio 6B at 30 Rockefeller Plaza. A dunk tank full of ice water, perhaps?

“I’m not nervous at all,” Emanuel said.

Chicago Mayor Rahm Emanuel promised to do the Polar Plunge because city kids met his goal of reading 2 million books last summer. (AP Photo/Andrew A. Nelles)

Chicago Mayor Rahm Emanuel promised to do the Polar Plunge because city kids met his goal of reading 2 million books last summer. (AP Photo/Andrew A. Nelles)

This isn’t the mayor’s first late-night rodeo. He was a guest on “Late Show with David Letterman” last September.

As for “Tonight,” “I’ve been asked before but this is the first time I’m going,” he said.

Fallon is famous for generating viral videos of him and his guests doing wacky skits and stunts, like the “nip sync” duet he performed Monday with “Brooklyn Nine-Nine” star and former pro football player Terry Crews.

Assuming the mayor doesn’t want to go shirtless on national television, would he be game for a lip sync battle with Fallon? Or a lip flip?

“We haven’t even talked about it,” the mayor said.

“I will be a good guest,” he added. “I will represent the city well.”

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