Paris and Benji party in Las Vegas on July 5.

Nicole Richie's well-documented metamorphosis from wrong-way-driving party girl into doting mom to baby Harlow may have hit a slight snag over the weekend. TMZ says she had a dustup with a woman at the valet stand of the Hard Rock Hotel in Las Vegas early Sunday morning. Security supposedly swooped in and removed Richie from the scene. Her rep, however, denies she was involved in a Sin City scuffle, insisting, "She was in Vegas but there wasn't an altercation of any kind involving her." Nicole was at the Hard Rock to catch boyfriend Joel Madden perform with his band, Good Charlotte, and she was snapped at the show hanging with sometime BFF Paris Hilton, who's still cleaving to Joel's twin brother and band mate, Benji. But, like Nicole, she can't quite escape her past. For the second time in two weeks, she had a close encounter with her Greek billion-heir ex, Stavros Niarchos. The Las Vegas Review-Journal says that as soon as the strapping Hellenic scion spotted Paris and Benji arrive at hot spot Blush around 2 a.m. Sunday morning, he "dashed out." Last month, Hilton was purportedly "glaring daggers" in Niarchos' direction when they crossed paths at a New York soiree.

Pete Wentz has found a captive audience for his emo musings. The Fall Out Boy bassist tells People he's constantly chatting up Ashlee Simpson's belly so his incubating progeny will eventually recognize him. "'The Expectant Father' tells you that the woman, when she speaks, the baby hears her all the time," he explains of the dad-centric baby guide. "And the father's voice isn't familiar unless you talk to it, so I talk to it all the time." As for the swelling-bellied Mrs. Wentz, he says she's craving pregnancy classics such as pickles and ice cream, adding that everything is "going well."

Jessica Alba has also been hitting the books to figure out what's best for month-old daughter Honor Marie. "I've been reading a lot about kids and infections, autism and vaccinations," the actress, who had some health issues as a kid, tells Britain's Sunday Express. "I've come to think that perhaps I was a product of my environment or the vaccines or something my mother took when she was pregnant." Jessica has also reached some nature vs. nurture conclusions over how she and husband Cash Warren will parent their tot. "Kids' personalities have so much to do with the parents and their mentality," she explains. "If you're very paranoid and uptight and won't let your child cross the street, they are going to take on that anxiety. If you're a little more laid-back and make your kids responsible for their actions, you'll probably have an easier time with them. I guess I'll find out." Alba is already showing off an enviably slimmed-down figure, but she says her diet has changed dramatically in the post-Honor era. "I used to be a just a coffee for breakfast, yogurt for lunch girl," she says. "Now I have to have something every couple of hours. I turn into Satan if I don't eat."

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