From PEOPLE Magazine Click to enlarge
Jennifer Aniston and Vince Vaughn acted out their share of cozy moments while shooting The Break Up in Chicago this summer. Back in the city on Oct. 12, they were ready for another one. The duo sipped cocktails with another couple on the terrace bar at NoMI, a swank restaurant with breathtaking views of the Windy City. Then they pulled a move straight out of the romantic comedy playbook: With temperatures dropping into the 50s, Aniston and Vaughn asked staffers for a blanket to ward off the chill and contentedly snuggled under the covers together. "She was all wrapped up," says an onlooker dryly, "with that guy she's supposedly not dating."

Indeed, Aniston and Vaughn's occasional off-hours party hopping and flirty dancing was easy to discount when cameras were rolling this summer. "Vince is my friend," Aniston—whose divorce from Brad Pitt became final Oct. 2—told this month's Elle. "He's delicious and funny...but I don't want to be a rebound girl." But now? With a multiday PDA-a-thon that saw the two openly kissing and cuddling at restaurants, nightspots and even the Wieners Circle hot dog stand, Aniston, 36, and Vaughn, 35, made it clear to pretty much all of Chicago—and the world—that they're a romantic item. Aniston's rep, who had previously denied rumors of a union, declined to comment on the pair's current status, as did Vaughn's.

There was no question things had heated up considerably, though, from the moment Aniston turned up at Vaughn's comedy show Oct. 11 and headed afterward to Holiday Club, an old haunt from the summer. "They were sitting at the bar, kissing and making out," says owner Tim Juliusson. "Before, I didn't think there was anything. But seeing them at the bar, you would say, 'That's a couple.' "

And apparently, a surprisingly serious one. Not only were Aniston and Vaughn spotted snuggling and reading the morning papers on her hotel terrace, he also brought her home to meet the folks. On Oct. 14 they visited Lake Forest, where Vaughn grew up, and ate lunch with Vaughn's mother, Sharon, and stepdad. The group later paused for more shopping at a nearby Target, where, says customer Barb Waxman, "I could not have been more shocked if a grizzly bear had been standing in front of me."

That's exactly how some pals have reacted to the news of the yoga-loving Friends megastar linking up with the Wedding Crashers goofball, a stalwart guy's guy who prefers flannel shirts to red-carpet glam. "Vince and her? Really? I see them as very different types of people, with different interests," says Vaughn's friend and Swingers costar Jon Favreau. But others see why Vaughn (see box) might attract the ex-Mrs. Pitt. "He's as funny and charming offscreen as he is onscreen," says his ]Be Cool producer Stacey Sher. "He's well-brought-up, he's polite, he's thoughtful, he's kind." Adds Crashers costar Keir O'Donnell: "He has an old-world quality about him, like a Frank Sinatra."

Still, "he hasn't had a relationship with somebody in a while," says a friend. Vaughn's only prior high-profile romance was with actress Joey Lauren Adams, whom he dated in 1998. But like his Crashers character, Vaughn seems to be mellowing with age. "Some of his friends are having babies and growing up," says the pal. "Maybe he is maturing."

Aniston would certainly know. She returned to Chicago for the final stop of Vaughn's Wild West Comedy Show tour (in which Vaughn emceed for stand-up acts) Oct. 11 at Chicago's Vic Theatre. The actress laughed and looked on as Vaughn glanced up at her balcony seat and waved. Once the show ended, Aniston stuck around for the wrap party. At first she and Vaughn kept their distance, but they quickly warmed up to one another, holding hands and stroking each other's back before kissing while boogying on the makeshift dance floor to "Funkytown."

The locations changed, but the lip locking results were the same over the next several days (see box). They were later spotted smooching Oct. 13 at Gibson's, a Chicago steak house, where s Aniston tried to pick up the tab until Vaughn thwarted her. "She was kind of sneaky," says Mario Lamas, who served them, "and gave somebody a credit card. But Vince is from Chicago and she was his guest. There's no way she was going to pay." Aniston was spotted kissing Vaughn on her hotel balcony later that night, as well as the following afternoon. They appeared on the balcony again early on Oct. 15, reading the morning newspapers. A couple of hours later, Vaughn was spotted by a guest downstairs in the men's spa, asking the attendant for a toothbrush. Says the guest: "He seemed happy."

Then again, Aniston has had that effect on him from day one of The Break Up, as the pair immediately clicked on-camera. "They loved working together," says costar Justin Long. "It's very palpable." However, it was restricted to before the cameras. "When I was on the set, they weren't [an item]," says Favreau, who also costars. "There was social interaction, but it wasn't overtly romantic." As rumors began to swirl—especially after the pair appeared especially touchy-feely at the Aug. 24 wrap party—the pair steadfastly denied a romance.

Aniston told Vanity Fair, "I adore Vince Vaughn, but I'm not going out with Vince Vaughn." Last month she pooh-poohed a question from Oprah Winfrey about her relationship with him. Vaughn, meanwhile, platonically lauded Aniston. "She's so easy to feel drawn to," he told Elle. "You can see why people are so enamored."

Some Aniston pals, in turn, were delighted with the friendship, which helped distract Aniston from what quickly turned into the summer of Brangelina. "She couldn't have picked a better person to spend a few months with while she's going through all this," pal Jason Bateman told Elle. "Vince really looks out for her." Especially now that things have turned romantic. "Vince brings out something in Jennifer that brightens her," says a source. "She's constantly belly-laughing when they're together. It's a joy to see."

  • Contributors:
  • Lauren Comander,
  • Kelly Williams,
  • Shia Kapos,
  • Barbara Sandler,
  • Tom Cunneff,
  • Lisa Ingrassia,
  • Brenda Rodriguez,
  • Nicholas White,
  • K.C. Baker.