'21 Jump Street' stars Channing Tatum and Jonah Hill make an unlikely pair of ...

There is no reason to believe that Jonah Hill and Channing Tatum would ever work well together in a movie, never mind become good friends.

One is short and stocky, the other tall and muscular.

One has the mouth of a sailor, the other the body of a god.

One made headlines by stripping weight, the other by stripping.

But make no mistake about it, the two actors maintain a surprising chemistry in the action comedy “21 Jump Street,” out Friday, due in no small part to their unlikely off-screen friendship.

“There was never really that moment of weirdness or awkwardness,” says Hill, 28. “It was just like, hey, want to be friends? Okay, cool, awesome.”

The two actors — clad in police T-shirts, shorts and shades — lounge around a room at a boutique hotel in SoHo. Tatum lies on the bed, staring out the window, while Hill sits at a table and sips a chunky green smoothie.

It feels like a fifth date where they each know everything about the other but are still genuinely interested in the conversation. They laugh a lot and speak in positive platitudes.

“I haven’t really gotten along with somebody that quick and easy and without a problem maybe, like, ever,” says Tatum, 31. “We just fell in step.”

And so begins Hollywood’s latest bromance.

There was Matt Damon and Ben Affleck in “Good Will Hunting,” then Brad Pitt and George Clooney in “Ocean’s Eleven/Twelve/Thirteen,” followed by Paul Rudd and Jason Segel in “I Love You, Man,” and now there’s Hill and Tatum in “21 Jump Street.”

But unlike previous bromances where both actors are handsome or funny or both, Hill and Tatum’s chemistry is unique because, well, the two actors are so incomparable.

A product of the South, the chiseled Tatum went from working as a stripper named Chan Crawford to dancing in Ricky Martin videos to modeling underwear to starring in romance and action movies.

Hill, on the other hand, grew up in Los Angeles, the son of a costume designer and the tour accountant for Guns N' Roses. He never stripped (thank God) or modeled underwear or danced with Ricky Martin, but received his big break as a comic actor in Judd Apatow movies like “Knocked Up” and “Superbad.”

Yet it is these disparate backgrounds that make their friendship work.

“We are from different parts of the world and experienced different upbringings and things like that,” says Hill, “but we are going after the same thing and we want to do it in the same way. That is rare.”

What is even rarer is a remake that is actually funny.