By People Staff
July 13, 2006 12:00 PM

Vegas, it’s not. The quiet farm town of Carthage, S.Dak., boasts 187 residents, two bars and a single diner. So it’s no surprise that Vince Vaughn hasn’t exactly been living it up. In South Dakota for two weeks to shoot the drama Into the Wild with director Sean Penn, the nightlife-loving actor has found time for hobbies like bowling and poker, but not with his usual zest. “He’s made it pretty clear that this isn’t his kind of place,” says a crew member. When Carthage retiree Arny Roos, an extra on the film, offered to get Vaughn tickets to a comedy club in Sioux Falls, he recalls, the actor politely declined. “He said, ‘As soon as I’m done, I’m outta here.’ ”

The costars (on June 21, 2005) first got cozy on the job amp#8211; shooting a Break-Up scene.

And back to a honey-haired beauty waiting in Malibu, biding her time meeting pals for cocktails, walking her corgi-terrier mix, Norman, gazing at the dolphins from the deck of her beach house – and missing her man. When Jennifer Aniston rang the front desk at the Holiday Inn Express in Winner, S.Dak., where the Wild cast stayed for a few days, it caused a sensation. “I was more excited by her calling than [Vince] being here,” says a clerk. “His cell phone wasn’t working, so we gave her his driver’s number.”

Those calls have helped make Vaughn’s time on the prairie a little less lonely. Until recently, though, the high-powered pair haven’t had enough time apart to miss each other. One year after getting together on the set of The Break-Up, Aniston, 37, and Vaughn, 36, have outlasted cynics who dismissed their relationship as merely a rebound romance or on-set affair. “They are very loving,” says a pal. “So clearly a couple.”

By October, work had led to play for the costars on the terrace of their Chicago hotel.

Behind closed doors, that is. During a Mexican getaway last month, locals say the intensely private duo rarely ventured out, spending time at the Punta de Mita estate of Girls Gone Wild producer Joe Francis. Back at home, Aniston and Vaughn are equally determined to keep a low profile. “When they walk outside, they are so aware [of paparazzi] and know not to do anything. Not even hold hands,” says the pal. “But when they are in private, they are very affectionate.”

Which begs another question, sparked by the 9.5-carat yellow diamond Suzy Fabrikant ring a source says Vaughn bought Aniston while the pair were in Europe promoting The Break-Up. So what of rumors Vince popped the question? Reps for both starsvehemently deny they are engaged. “The engagement stories are fabricated,” says her rep, who also denies Vaughn gave Aniston the ring. (Aniston herself has called such talk “silly.”)

Still, there’s no doubt the relationship has shifted into something more serious, evidenced in part by Aniston’s willingness to troop along with Vaughn to view Chicago real estate and a recent openness on the part of the pair to discuss one another. Promoting The Break-Up in Paris, Vaughn said of Aniston, “She’s the most sincere woman I know. She doesn’t lie, she has a good heart.” In the June issue of Harper’s Bazaar, Aniston said that Vaughn was “a very deep human being, incredibly smart, loves history, is protective and very loyal to his family and friends.” Plus, says a friend, “He’s hilarious. He makes her laugh. That’s a big part of the attraction.”

Aniston and Vaughn at the French Open in June

Big enough to transform Vaughn from what one source called “the forever-bachelor type guy,” who a year ago loved to close down Chicago clubs with buddies, to a one-woman man. Now when Vaughn visits home, he is more likely to catch a Cubs game with Aniston, as they did on Memorial Day, than hit the singles’ scene. Says Tim Juliusson, owner of the Holiday Club, where Vaughn took Aniston last summer: “They’re in couples-mode now.”

Much to the delight of his mom, Sharon Vaughn, 64, a former hedge-fund manager in Lake Forest, Ill. As Vaughn told a French reporter in June, “My mother, who’s impatient, asks me all the time when I’m going to stop working so hard so that I can give her grandchildren.” The time, he added, may be nearing: “As I get older I’m becoming more open to the idea of meeting the right person and starting a family.”

"Jen and Vince were very relaxed and happy in each other's company," a source says of the couple, who had dinner at the Plaza Athamp#233;namp#233;e on June 12.

And if that person is right, what do a few tiny differences make? Aniston is a self-professed “control freak” who likes to eat right, work out and scour the kitchen before she goes to bed. Vaughn? “I eat too much, I smoke too much, and I even drink too much sometimes,” he said recently. But those who see beyond his guy-who-leaves-the-toilet-seat-up side (yes, he once admitted he does) call him a gentleman who, says Chris Eiserman, his volleyball coach at Lake Forest High, is “kind to everyone.” That kindness plays well with Aniston, who has had a famously tumultuous personal life. Though she has said she wants to remarry, she approaches intimacy with caution, telling Bazaar, “You’ve got to feel safe with somebody.” And that’s worth more than any ring. The bond between Aniston and Vaughn, which began, he has said, as “instant chemistry,” has now grown into something diamonds can’t outshine. Says the pal: “They are very much in love.”

• By Karen S. Schneider. Lauren Comander, Shia Kapos and Barbara Sandler in Chicago, Bryan Alexander, Alexis Chiu, Lycia Naff in L.A., Kate Klise in Carthage, Theresa Braine in Mexico City, Peter Allen in Paris and Jenna Good in Sydney