08/22/2005 at 01:00 AM EDT
Hard to believe, but Maddox Jolie's 4th-birthday party on Aug. 6 was far less elaborate than those of plenty of kids who don't spend their days jet-setting around the world with their superstar mom and her superstar boyfriend. No pony rides or bouncy houses, just a kiddie pool, Angelina Jolie
and Brad Pitt
—along with Maddox and his newly adopted sister Zahara—and a group of friends celebrating at Pitt's Santa Barbara beach house. Over at the actor's Malibu home base, a room is now reserved for Maddox. Pitt reads to him and "spends time playing" with both children, says a source. "He is very kind to them."
So is he Brad the Dad—or Brad the Cad? In the wake of Jennifer Aniston
's buzzed-about interview with Vanity Fair
—in which she portrayed her ex as sometimes distant and lacking a "sensitivity chip"—Pitt has been getting even closer with Jolie, smooching in plain view on a getaway to Arizona before the birthday bash. Meanwhile, baring her soul seems to have bolstered Aniston, who stepped out for sight-seeing in Chicago and gamely greeted fans ("That's okay, you don't need him anyway, Jen!" yelled one) outside the Japonais eatery on Aug. 7, where she dined with a group that included Vince Vaughn, her costar in the now-shooting comedy The Break Up
. A few days earlier Aniston, 36, was spotted eating out with Pitt's mother, Jane, 65. The women's ongoing friendship "is what it is," says Pitt's brother Doug. "No more, no less."
In light of the VF
interview, "you see a side of Jennifer you didn't really see before and people didn't really know," says celebrity publicist Lizzie Grubman. As for Pitt, since the piece came out, "the best thing Brad's done is just kept his mouth shut," says a top Hollywood public relations exec. But if Pitt, 41, and Jolie, 30, are maintaining their public silence, their actions loudly attest to the seriousness of their romance. On Aug. 1 the pair landed (with Jolie at the controls of a private plane) at the airport in Lake Havasu City, Ariz., where they shared "one big, long kiss," says airport staffer Dean Lowery. After booking a room at the Agave Inn—their arrival was "a walk-in kind of deal," says an observer—the pair hit the Javelina Cantina next door, where a security camera caught Jolie grinning widely at Pitt before the pair kissed. The next morning saw the duo chowing down on pancakes and bacon (her) and French toast (him) at the local IHOP, where they were "very nice, polite, smiling, courteous," says waitress Carol Sexton.
IHOP? A weekend partying by the kiddie pool? Could the International Couple of Mystery be going domestic on us? "They're very laid-back...like they've been together for a while," says a source close to the couple, "and are comfortable with each other."
Michelle Tauber. Lauren Comander and Kelly Williams in Chicago, Kerri Smith in Lake Havasu City, Julie Jordan, Lycia Naff and Nicholas White in Los Angeles, K.C. Baker and Joanne Fowler in New York City and Kate Klise in Springfield, Mo.