Is Jennifer Aniston a Homewrecker?

Her new boyfriend's ex-partner moved out after he started dating Aniston.

June 15, 2011— -- Jennifer Aniston knows how it feels to be a wronged woman after her ex-husband Brad Pitt took up with Angelina Jolie.

Now, Aniston is being accused of wronging another woman -- the ex-partner of her new boyfriend Justin Theroux.

Hollywood costume designer Heidi Bivens is said to be "devastated" after Theroux abruptly ended their 14-year relationship as he became close to Aniston.

"Heidi and Justin have been together for 14 years," Bivens rep confirmed to the New York Post. "They met when she was 20 years old and he 24, and yes, she just moved out of their home last weekend. She has no comment."

Aniston's rep had even less to say about the report.

"We try not to respond to the endless rumors that appear in gossip columns and tabloids," her spokesman said in an e-mail to ABCNews.com.

Theroux's rep did not respond to ABCNews.com's request for comment.

"The reason this story is so big is because Jennifer is the most famous woman to have a homewrecker change her life," Popeater gossip columnist Rob Shuter told ABCNews.com. "It became her brand. Only six months ago, her friend Chelsea Handler called Angelina Jolie a homewrecker."

But is Aniston a homewrecker?

"The implications to Jennifer are really quite enormous," he said. "I don't know if she's thought this through. She's that sweet girl, that friend who's never going to betray us. If she did steal someone else's man it's going to hurt her brand.

"Once you have been labelled something it's very hard to get past it, even if it's not true," Shuter added.

Aniston, 42, and Theroux, 39, first became friendly on the set of "Wanderlust" in the fall, according to People magazine.

Aniston has been known to fall for her co-stars. Remember Vince Vaughn? Gerard Butler?

But Theroux is different. For one thing, he doesn't have those dashing leading-man looks.

He's darker and scruffier and more likely to be cast as the villain: He was Drew Barrymore's evil ex in "Charlie's Angels Full Throttle" and the evil wizard Leezar in this year's "Your Highness."

He can play drama or comedy, big or small screen, and he has serious writing cred. He co-wrote the comedy hit "Tropic Thunder" and, on the recommendation of star Robert Downey Jr., wrote the screenplay for "Iron Man 2."

"He's a little edgier than the guys she's been out with, but they're having a really good time," People magazine reporter Lesley Messer told ABC News Now's "What's the Buzz." "Apparently, she's really happy."

So happy, that she went public with the romance last week when the couple made an appearance at the MTV Movie Awards after-party at the Soho House in Hollywood.

"She's not hiding this," Shuter said. "She has no shame in this."

Last month, Aniston threw a small get-together to introduce Theroux to her best pals, Chelsea Handler and Courteney Cox, putting to bed rumors that she and Cox were on the outs.

Cox apparently approved of Aniston's new beau.

"They all had a great time and enjoyed Justin's company," a source told People.

"Either we're seeing another side of Jennifer for the first time or a brand new Jennifer," Shuter said. "But she does seem to be changing up her life."

Aniston recently put up for sale the Los Angeles home she spent years renovating and has purchased a new pad in New York, where Theroux is based.

Aniston Bares It All

She's also departing from her typical girl-next-door roles.

In her new movie, "Horrible Bosses," the queen of romantic comedies will play a "sexually aggressive" dentist who harasses her male assistant, played by Charlie Day.

That's not all. Later this fall, Aniston could also appear topless in Judd Apatow's "Wanderlust," the film that brought her together with Theroux.

Aniston and Paul Rudd play a couple who drop out of the rat race to become hippies. Aniston not only rips off her shirt but smokes pot and has a threesome, according to HollywoodLife.com.

"No more victim roles," Shuter said. "No more girlfriends who have been dumped roles that mirrored her life. She's ready to spice things up. And if the public turns their back on Jennifer, she has enough money from her 'Friends' residuals."