Jennifer Aniston and Justin Theroux to be Married by 2012 Year End?

Jennifer Aniston has vowed to be married by the end of the year.

The 43-year-old actress – who has been dating Justin Theroux since they met on the set of ‘Wanderlust’ two years ago – has reportedly told close friends that the actor is ”the one” and has even joked that she has given him an ultimatum to propose by the end of 2012.

According to the Daily Mirror, Aniston quipped:

“If [Justin] hasn’t got down on one knee, or we’re not married, by the end of the year, it’s over!”

Meanwhile, Aniston explained the couple’s new dog Sophie, a boxer-pitbull cross, is a trial run for having actual children.

The Daily Mirror newspaper quotes Jennifer as telling a pal:

“[Justin and I] are constantly laughing. Now we’ve got our new baby things are getting serious. We have new responsibilities.

“[Sophie's] like a test run for kids, I guess… although hopefully kids are easier to house-train. We argue over who takes the dog out and who disciplines her, but that’s about it.”

Jennifer – who cemented her place on the Hollywood Walk of Fame last week – has also told pals that things with Theroux are “fabulous” and that she has ”never been so happy”.

A friend added: ”Jennifer has never been so happy romantically. She and Justin have discussed their long-term future and both agreed that they love the idea of settling down. The onus is now on Justin to pop the question.”

Watch the clip below as Jennifer gushes about Justin on the Ellen DeGeneres show:

What do you think readers: Will Jennifer Aniston and Justin Theroux be engaged or married by the end of 2012?