David Letterman on “Jimmy Kimmel Live!” (Jeff Neira/AP)

David Letterman’s visit with No. 1 fan Jimmy Kimmel churned up the biggest Wednesday audience in “Jimmy Kimmel Live’s 10 year history — about 2.4 million viewers.

“I’m more excited than I’m able to explain,” Kimmel gushed as he introduced Letterman to his studio audience at the Brooklyn  Academy of Music.

Kimmel, who usually tapes his show in Hollywood, went to Brooklyn for a week, only to have to pull the plug on Monday’s show, owing to Sandy.

Tuesday’s show went off as planned; ditto Wednesday’s with Letterman, and it will go down as one of the most torrid bromance scenes in TV history.

“I’m a little bit overwhelmed,” Kimmel said demurely, when Letterman took the guest chair, noting it was maybe similar to when Johnny Carson visited Letterman on his show.

Letterman said the big difference was that “Johnny Carson was something… and I’m not much of anything, was the big difference.”

Kimmel pshawed, then showed Letterman photos of Young Kimmel with a “Late Night with David Letterman” birthday cake, and a “Late Night” license plate on his car.

Very creepy.

“This is serious for me. This could make me or break me tonight…I hope I’m not making you uncomfortable,” Kimmel said.

Very, very creepy.

“I’m more concerned for you – did your parents step in? These are warning signs, Jimmy,” Letterman quipped.

Then, surprisingly, Letterman began to fawn over Kimmel:

“In show business one of the precepts is that you’re not supposed to be really nice to people — especially if you have the same occupation as the other person.

“Jimmy has broken that precept and been nothing but generous and courteous and kind to me and my entire crew,” Letterman said.

“I’ll be honest with you, it was troubling. I kept saying to people, ‘Why is he sucking up to me?’... When I was persuaded that there was some measure of stability here, then I really realized that it was genuine and I couldn’t appreciate it more.

Here’s the interview: