Scarlett Johansson and Jessica Simpson may not have much in common beyond their blond hair and impressive ability to fill out a sweater, but it seems they're both in serious demand when it comes to bringing the seedy world of adult entertainment to the big screen.

First up is Scarlett, who, if you believe the British tabloids, has signed on to star as porn queen Jenna Jameson in the adaptation of her best-selling and surprisingly well-reviewed autobiography, "How to Make Love Like a Porn Star: A Cautionary Tale."

"I tapped up Scarlett for the part and I'm very excited about the film," the alarmingly attenuated and much-altered sex siren is quoted as telling Britain's Daily Express. "It was my decision not to play the role because I've lived that life already and anyone can play themself."

Uh-huh.

While Jameson has gushed for months that the A-list beauty-cum-Woody Allen muse would be the perfect choice to headline her lurid tale of sex, drugs and award-winning girl-on-girl action (hey, she's a member of the prestigious X-Rated Critics Organization Hall of Fame), it looks like she's barking up the wrong bombshell.

Johansson denies any and all involvement in the sure-to-be skin-heavy flick.

"There is no truth to this," Johansson's spokesperson, Marcel Pariseau, pooh-poohs to MSN Entertainment. "Scarlett has never seen a script nor been approached about this project. She also has no interest in playing this role. It is wishful thinking on the part of Ms. Jameson."

Johansson isn't the only one steering clear of doffing her duds in the name of her art. Simpson was also approached for a provocative porno part, which was quickly rejected by her double-D-admiring dad, Joe.

"The last script that came to us was for Jessica to be a porn star," he tells People (it's unclear whether this was also the Jameson project). "We were promised we would win an Oscar with that."

If the idea of Jessica clutching a gold bald guy is unsettling, it's nothing compared with Joe's use of the plural pronoun when he adds, "I was like, 'Eh, we'll just buy a [statue of a] little man and keep our clothes on.'"

(Anyone else go to a scary visual place? Must just be us.)

Jessica is currently hard at work on the sure-to-be-Academy-acknowledged "Major Movie Star," in which she plays a spoiled celebrity who joins the Army.

The stacked starlet thespian is taking her camouflage-filled role seriously, telling People, "I was surprised at how cute the outfits fit!"

Next: Romance Report: Bono & Cruz, Jessica & Cash