The engaged couple was photographed arriving on Friday, Dec. 27 in Mexico, a traditional destination for the duo this time of year.
The We're the Millers starlet, grinning as she made her way around the airport, looked casual chic for the warm temperatures, wearing a green blouse, skinny jeans, nude wedges, aviators and her beautiful engagement ring. Theroux sported a dark gray sleeveless T-shirt, black pants and black boots.
The couple seemed "happy, relaxed and looking forward to their break," according to a source. Several friends joined Jen and Justin and the group is all staying at the same resort while they ring in 2014.
Before jetting out of Los Angeles, the pair celebrated Christmas with some of Theroux's family, including his mom, at their recently renovated home in Bel Air, another source reveals to E! News.
The Friends star and her beau were photographed arriving at the bash, carrying gifts wrapped in purple paper with a silvery blue bow. The 44-year-old beauty smiled as she made her way to the party, sporting a blue blouse with a white camisole, a green jacket and sunglasses.
Aniston and Theroux are longtime friends of the parents-to-be and coincidentally jaunted to Cabo with them last year for a post-Christmas vacation.
—Additional reporting by Michelle Falls