First Nick, now Joey! Porn star Jessica Jaymes has a huge appetite for members of boy bands.

The red-hot brunette got Nick Lachey of 98 Degrees into hot water with his wife Jessica Simpson, as The ENQUIRER previously revealed, when she put on a steamy X-rated girl-on-girl show during a bachelor party for Nick’s longtime soundman.

Now comes word that the 25- year-old porn queen got cozy with *NSYNCer Joey Fatone in Las Vegas last January — just six months after he’d gotten engaged to his high school sweetheart Kelly Baldwin!

Joey, 27, married Kelly — the mother of their 3 1/2-year-old daughter — in a lavish September 9 ceremony at Long Island, N.Y.’s Oheka Castle. Jessica — Hustler magazine’s Honey of the Year — had hooked up with Joey during the Adult Entertainment Expo in Las Vegas, say sources.

“They struck up a conversation at one of the Expo booths on January 8, and one thing quickly led to another,” said a pal of the pornagain actress.

The sex star had brought her fiance to Vegas with her — and she didn’t want to get caught with Joey. So she took Joey to a female friend’s suite and allegedly made love to him — while her friend was asleep in another room, said the pal.

Continued a source close to Jessica: “Joey was immediately taken with Jessica — and she was especially impressed because Joey was a fan of some of her films. “Jessica told me, ‘Joey and I got together and ended up fooling around. He was really sexy and very sweet to me.’ “

The next night the porno princess flashed her breasts at a disco in the Hard Rock Hotel during a party sponsored by Hustler magazine. And Joey was on hand to catch all the “fun.”

“Jessica had undoubtedly told Joey she was going to be there because Joey showed up — along with fellow *NSYNC singer Lance Bass and Backstreet Boy A.J. McLean,” said the pal.

But that wasn’t the end of it. “Jessica told me that she saw Joey for a while after their first night,” confided the close source. “It was a quick, torrid affair that flamed out after a few weeks.

“Jessica never mentioned to me that Joey had a fiancee at the time of their little fling, but I don’t think he ever told Jessica.

“I’m sure that when Joey’s wife hears of his torrid affair with Jessica, she’s going to really give him hell.”

Concluded the pal: “Jessica must have this thing for boy band members. Someone better tell Cameron Diaz to lock up Justin Timberlake!”