Justin Theroux and Jennifer Aniston
Cast member Justin Theroux and actress Jennifer Aniston arrive at the season premiere of HBO's "The Leftovers" in New York June 23, 2014. REUTERS/Andrew Kelly Reuters/Andrew Kelly

Jennifer Aniston and Justin Theroux are reportedly set to hit the altar for their "I Dos." However, a recent report claimed their wedding may not happen as Justin has allegedly been cheating on his fiancé by flirting with other actresses.

"The Leftovers" actor was allegedly getting "intimate" with several other women according to Life & Style.

Justin Theroux was caught getting flirty with "Girls" actress Allison Williams at the Emmy Awards after-party on Aug. 25. An eyewitness claimed he was really cosy with her.

"He twirled a cigarette, joked and flirted with her," the eyewitness told the publication.

If that wasn't enough, he reportedly also had his eyes set on Paula Patton during the party. The source added Justin Theroux and Robin Thicke's ex-wife could have kissed since "they huddled so close, their lips almost met."

However, Jennifer Aniston reportedly already knew about her fiancé's wandering eye.

"After friends tipped Jen off about his behavior, she ripped him a new one," an insider told the mag.

But there was never any wedding planned to begin with, according to Huffington Post.

In an interview with "The Talk," Jennifer Aniston denied any wedding preparations. When asked whether her marriage to Justin Theroux won't push through, the actress replied, "There was no wedding planned."

However, she did say that she and Justin feel like they are "already married."

The "Horrible Bosses" actress went on to slam all the gossips and rumours about her relationship with Justin Theroux.

"They're loaded with absolute false information ... They like to create the story, because it's not interesting that we're just really happy, and in love," she told the ladies of "The Talk."

Additionally, a source also told US Weekly that the couple is in no hurry to walk down the aisle. For now they are said to be basking in the feeling of being engaged. The source claimed if they do get married, they would want to have a simple ceremony, "something casual."

Justin Theroux and Jennifer Aniston have yet to announce an official wedding date. As for the cheating rumours, Justin Theroux has yet to comment on any of the allegations.