Jennifer Vaughn?

Here's the new rumor....

JEN & VINCE: The Wedding's On! Brad's mom is invited - and so is his sister! When Brad Pitt's mom, Jane, answered the phone at her Missouri home in late June, it wasn't her darling son or the mother of his child, Angelina Jolie, on the line with an update on baby Shiloh. To her surprise, it was Brad's ex-wife, Jennifer Aniston, calling with some exciting news -- and a very special invitation!

Jen told Jane that Vince Vaughn had proposed to her while they were in Paris and went on to ask her ex-mother-in-law if she'd honor her with her presence at the wedding! "Jane said there's no way on earth she'd miss it!" says an insider. "She's remained very close with Jen since her breakup with Brad. She says she still considers Jen her daughter." Jane asked Jen if she'd set a date, and Jen said it's still being discussed. But the insider says Jen told Brad's sister Julie, who's also invited, "I'd like it sooner rather than later."

Jen keeps her ring under wraps. With the engagement news out and her fiance working to get fit, why isn't Jen showing off the 9½-carat canary diamond that Vince, 36, presented to her with his proposal? Friends say it's because she and Vince are waiting for Brangelina's baby news to die down. The couple's daughter Shiloh was born on May 27, but Brad and Angie only moved back to Malibu -- just 13 miles from Jen and Vince's house -- on June 10, so they're still the talk of the town. And Jen has no problem keeping things that way."This is Brad and Angelina's moment," says an insider. "It'd be tacky for Jen and Vince to announce the engagement so soon after Shiloh's birth."

And Jen is in no rush to make an official engagement announcement. She told her pal, "I'll share it with everyone when I want to."Sorting out the detailsThere are still lots of decisions to be made about where and when the happy couple will say "I do," but Jen knows one thing: She wants this wed ding to be completely different from the $1 million beachfront extrava ganza she and Brad had in July 2000, which was complete with 50,000 flowers, a Greek bouzouki band, a Frank Sinatra impersonator and fire works. This time, Jen wants to keep things simple, spiritual and dignified."That's fine with Vince," says another pal. "He'll do whatever makes Jen happy. He joked that he'd wear a wet suit and tie the knot underwater if it's what she wanted."Jen's reply? "A tux will be fine!"

The couple are leaning toward having the wedding in Chicago, Vince's hometown -- and where they fell in love while filming their hit movie."There will be more of Vince's Chicago friends than Jen's Hollywood crowd," says an insider.But there will definitely be at least one A-lister in attendance."Jen's already asked Courteney Cox to be her matron of honor," says the insider. When Jen married Brad, she had two old friends as bridesmaids. But she and Court have become so tight in the last six years that Courteney's the one Jen turned to when Brad walked out. Naturally, Court's daughter, Coco, 2, who is Jen's godchild, will be her flower girl."I'm so happy," Jen told the first friend. "I really feel like this is the beginning of a new life."