MISS Congeniality is dating a “Monster.” Sandra Bullock, America’s girl next door, has fallen hard and fast for tattooed mechanic Jesse James, the bad-boy star of the hit hot rod TV show, “Monster Garage.”

And they don’t come much badder than the biker mechanic, whose great-great-grandfather was a cousin to the famous outlaw, Jesse James.

Bullock’s new lover dumped his porn star wife Janine Lindemulder when she was seven months pregnant — and began dating Sandra just a month before his youngest daughter was born.

“His friends can’t believe how he went from a porn star to Sandy,” said a pal of the chopper building hunk.

“They can’t believe she wants to be hooked up with Jesse, who’s covered in tattoos and was a juvenile delinquent!”

Adds an insider: “They are the oddest couple in Hollywood.”

A source close to the new lovers told The ENQUIRER Sandra met James in December when she brought her young godson on a tour of the hit Discovery Channel show “Monster Garage,” which films at West Coast Choppers, a custom motorcycle builder in Long Beach, Calif.

“Jesse instantly was smitten with Sandra, and minutes after she left the garage, he called her and asked her out to dinner,” says the insider.

“Jesse desperately wanted to impress Sandra on their first date so he went out and bought a convertible Porsche from professional wrestler Bill Goldberg.

“Well, when Sandra hopped into Jesse’s new Porsche, she liked it all right — because she has one just like it!

“As it turned out Jesse didn’t have to impress the movie star. Sandra had already fallen for him.”

The gruff and grimy gearhead told his pal: “We hit it off right from the start. It was like magic.”

Since then, the new duo has been closer than two spark plugs in a ’57 Chevy.

“Every night, she’s at his place or he’s at her place,” said the pal. “Jesse says he’s amazed at how similar their tastes are.”

But friends are calling it a case of extreme opposites attracting!

“Jesse’s taste in women usually leans toward the Pamela Anderson, fake boobs type — not the girl next-door,” said the insider. And Sandra, 39, doesn’t usually go for the tattooed mechanic types either.”

In the past, she has dated fair-haired boys like actor Matthew McConaughey, Tate Donovan and Ryan Gosling.

“But this time, she’s got the poster boy for ‘bad boys,’ ” said the insider. His idea of cuddly pets includes his two pit bulls and a fish tank full of sharks.

Jesse, 34, was such a wild teenager he did time with the California Youth Authority for stealing cars.

But his passion for cars and motorcycles made him a star.

After he became known for building custom choppers for Shaquille O’Neal, Keanu Reeves and Kid Rock, the Discovery Channel chose him to star in a show about customizing cars called “Monster Garage.”

He now makes $6 million a year.

He divorced Karla James, the mother of his two kids, and married porn star Janine, who is known for her girl-ongirl videos, on Oct. 20, 2002. They separated 13 months later and his daughter Sunny was born January 1.

Sandra’s publicist confirmed she and Jesse are “good friends,” but denied they are having a romance.

Her publicist also confirms they met when Sandra brought her godson to the show.

Sources say the macho mechanic’s divorce has gotten messy. He’s demanded a DNA test, to prove he’s the father of her new baby, and Janine has refused to do it.

On November 10, he filed for a restraining order against Janine, claiming that she has hit him in the face with a cellphone, slammed a bathroom door on his head and tried to run him over with a car.

But Janine’s mom Jonlyn Jeter told The ENQUIRER that Jesse has attacked Janine, throwing a water bottle at her and dragging her on the ground by her hair.

“He told me he was dating Sandra Bullock, but she won’t put up with him for long,” Jonlyn said.

Surprisingly, instead of sounding bitter, porn princess Janine told The ENQUIRER she’s actually rooting for Jesse and Sandra to make it.

“I’m glad Jesse’s found another woman to make him happy,” she insists. “He could not have found a better chick than Sandra Bullock. I say ‘You go, girl!’ I hope it works out for them.” — JOHN SOUTH and RICK EGUSQUIZA