If a fight broke out, who would survive? Brad colludes with Angelina's kinda incestuous brother. Matthew Fox's stripper may have faulty memory. Madonna's boytoy stands in a corner and cries. Another day, another reality star sex tape. Thursday gossip arrives.

Halle Berry walking downtown with a friend yesterday ... a grumpy-looking Ron Perelman leaving Bar Pitti on Sunday... Alex Rodriguez walking to lunch at Da Silvano ... Mary-Kate Olsen getting coffee with Nate Lowman in Tribeca ... Phoebe Cates getting breakfast with a friend yesterday at Yura on Madison Avenue ... Nicole Kidman walking on Park Avenue ... Naomi Watts shopping at Lilliput on Lafayette Street ... Chaz Bono arriving at JFK ... Julianne Moore and Bart Freundlich walking with their daughter and dog in the West Village ... Taylor Momsen filming scenes for Gossip Girl ... Hugh Jackman bowling with his kids at Lucky Strike on Sunday alongside Vincent D'Onofrio and his son ... Luke Wilson leaving Nello's on Sunday with a lady friend ... Heidi Montag and Spencer Pratt arriving at JFK ... and Keith Urban leaving his apartment building with his daughter.

[Mary-Kate Olsen, her boyfriend Nate Lowman, and his hat try to find barbershop quartet rehearsal in Paris on Saturday. Image via Bauer-Griffin]

[Princess Coldstare Leigh Lezark looks just like a bird nesting in the front row of the Giambattista Valli Pret a Porter show in Paris today with Nate Lowman, Mary-Kate Olsen, and Margherita Missoni. Image via Getty]

• Mary-Kate and Ashley Olsen and their boyfriends, Nate Lowman and Justin Bartha, had super evening out the other night. It involved steak, making out, tickling, and "chain-smoking cigarettes until after 4am." [P6]
• Derek Jeter and Alex Rodriguez aren't on the friendliest terms these days. Now things have turned frosty between their respective girlfriends, Minka Kelly and Kate Hudson. [P6]
• Heidi Pratt appears in the new issue of Playboy. But you won't find any nude pics of her in the magazine. She says she won't strip down completely until after she has a few "upgrades" performed by her plastic surgeon. [Us]
• Kourtney Kardashian is pregnant. So who's the father? Either she's not saying because she plans to use the news to gin up ratings for her crappy reality show, or becaue she doesn't know herself. One or the other. [E!]

• "Real Housewife" Kelly Killoren Bensimon has deceived us all once again. All the talk about her Ivy League education? Turns out she took classes at Columbia's extension school and anyone can do that. In related news, Jill Zarin supposedly tried to return a dress at Intermix with a big stain on it. [P6]
• Kelis—who is seven months pregnant—has filed for divorce from Nas. [NYDN, People]
• Marc Jacobs admits Madonna did ask him to help Jesus Luz get a work visa, but says it's "no big deal" since he'd "do anything to help a friend." [NYDN]
• An Austrian radio station now says it was responsible for hiring a Beyonce lookalike to fool a Vienna museum. [Us]
• Rachel Zoe flew first-class from LA to NYC. Her husband, however, was forced to fly coach. The indignity! [NYDN]

Olivia Palermo carrying a Marc Jacobs shopping bag in Soho ... Sarah Jessica Parker shopping at Kidding Around on West 15th Street ... Edie Falco standing on the sidewalk holding a cup of coffee in Soho ... Hugh Jackman arriving at JFK ... Robert De Niro peering into the tinted window of an SUV ... Bar Refaeli hailing a cab ... Juliette Lewis carrying an iced coffee ... Brad Pitt shooting a Japanese commercial with a Sumo wrestler ... Elizabeth Hurley leaving a hotel with Arun Nayar ... Samantha Ronson walking ... Tilda Swinton shopping with a friend ... Kelly Ripa leaving a building with an Oscar Blandi bag ... and Mary-Kate Olsen getting breakfast in Tribeca with Nate Lowman.

Kelly Ripa carrying son Joaquin ... Anne Hathaway walking downtown with boyfriend Adam Shulman, and later taking her dog for a walk ... Beyoncé arriving at JFK ... Uma Thurman eating ice cream with son Levon and a friend in Midtown ... Mary-Kate Olsen riding a bike in the East Village with Nate Lowman ... Kim Kardashian looking like a tourist in Soho, and later getting a pedicure at a nail salon ... Katie Holmes standing on a sidewalk on the Lower East Side ... Elizabeth Hurley and husband Arun Nayar glaring at another couple on Madison Avenue ... Whitney Port walking in Soho ... Russell Crowe leaving his hotel ... Lindsay Price talking on her cell in the West Village ... Diane Kruger and Joshua Jackson holding hands in Soho ... and Naomi Watts standing under an umbrella on a movie set in Brooklyn.

Yves Saint Laurent sponsored the Metropolitan Opera's 125th Anniversary Gala at Lincoln Center on Sunday night. YSL creative director Stefano Pilati was on hand to welcome the likes of Brooke Shields (left), Claire Danes, Claudia Schiffer, Kanye West and Amber Rose, Parker Posey, Kim Heirston, Mia and Patrick Demarchelier, Diane Kruger and Joshua Jackson, Richard Meier, Jeremy Irons, Willem Dafoe, Ingrid Sischy, Emily Mortimer and Alessandro Nivola, Sally Singer, Woody Allen, Stefano Tonchi, James Levine, Renée Fleming, Peter Martins, Julianna Margulies and Keith Lieberthal, Zoe Saldana, Daphne Guinness, Julie Macklowe, Plácido and Marta Domingo, Ginnifer Goodwin, Becki Newton, Patricia Clarkson, Austin Scarlett, and Met mega-donor Mercedes Bass. [PMc, Wireimage, Style.com, VF, FWD]

♦ For his spring campaigns, Marc Jacobs is eschewing celeb-muses like Meg White and Posh Spice: He's cast Israeli model Raquel Zimmerman for his Collection ads, British model Daisy Lowe for Marc by Marc, and Ryan McGinley for men's. [WWD]
♦ Are you a pregnant Project Runway fan? Then march (or waddle) over to the West Village tomorrow to meet Christian Siriano when he unveils his maternity line, Fierce Mamas. [The Cut]
♦ Plans for a Barneys store in the meatpacking district are definitely underway. The most likely location is on West 13th Street. [The Daily]

Mary-Kate Olsen smoking during lunch with boyfriend Nate Lowman ... Jeremy Piven hailing a cab outside Balthazar ... Robin Williams leaving his hotel ... Mad Men star Elisabeth Moss crossing the street with a Starbucks cup in hand ... Brad Pitt getting in an SUV outside the Michael Kors boutique on Prince Street and later stopping off at Mercer Kitchen ... Kim Raver, Brooke Shields, and Lindsay Price filming scenes for Lipstick Jungle ... Katie Holmes walking to a yoga class and later carrying Suri into their East Village apartment building ... and Ed Westwick walking on the Upper East Side.

♦ Present at Bette Midler's Hulaween benefit gala for the New York Restoration project: Suze Orman (dressed as big pile of money, left), André Leon Talley, Gloria Estefan, Gloria Gaynor, Donna Karan, Kathy Griffin, Michael Kors, Pink, Jimmy Buffett, John McEnroe and Patty Smyth, Ray Kelly, and Cindy Adams. [PMc, Wireimage, NYO]

♦ At Marc Jacobs, there were lots of celebs like Helena Christensen, Elijah Wood, Nicole Richie, Stephanie Seymour, Kelly Osbourne, Sofia Coppola, Winona Ryder, and Jennifer Lopez, and the elaborate, adventurous, world travel-inspired clothes got high marks—but all of the above was entirely eclipsed by the presence of Posh Spice's new gamine haircut. [WWD, Telegraph, Hello]