02/27/2012 06:12 pm ET Updated Feb 27, 2012

Jennifer Aniston Justin Theroux Marriage: Actress Reportedly Says 'It's Over' If Theroux Doesn't Propose

According to British tabloid The Daily Mirror, it's only a matter of time before Jennifer Aniston and Justin Theroux tie the knot.

The 43-year-old actress allegedly told a friend that Theroux was "The One" at an exclusive pre-Oscar party at Drai's in Hollywood on Friday, and jokingly revealed that she had given the actor an ultimatum.

"If he's not got down on one knee [sic], or we're not married by the end of the year, it's over!" Aniston reportedly said.

The actress also reportedly told her friend that things were "getting serious" with Theroux -- especially because their new "baby," a pitbull-boxer puppy named Sophie. "We have new responsibilities. She’s like a test run for kids, I guess," Aniston allegedly said.

But is the star, who split from her husband of four and half years, Brad Pitt, in 2005, really ready to settle down again?

In October 2011, she told HELLO! magazine that she had absolutely no plans to marry in the near future: "I am not planning to get married any time soon. This ring that I'm wearing is not an engagement ring. I've been married once and I don't know if I'll get married again, but I can tell you that as of this very moment, as of today, I have no plans to get married."

That hasn't stopped the rumors of couple's impending nuptials, though. A November 2011 issue of OK! magazine reported that Aniston and Theroux were were planning to elope in Cabo San Lucas, Mexico over the holidays (they didn't), and just a few months before that, OK! proclaimed that the couple was competing with Brad Pitt and Angelina Jolie for the year's best nuptials. Neither couple is married.

Aniston and Theroux met two years ago on the set of "Wanderlust," and first stepped out together as a couple in June 2011. They moved into a house in the Hollywood Hills together in September 2011.