Jennifer Aniston  and Justin Theroux arrived in Mexico on Saturday, just in time to finish out 2013 with a bang. The couple was accompanied by their frequent guest and Jimmy Kimmel's wife, Molly McNearney. The Mexican vacation comes at the end of a fun month for Jennifer. A few weeks ago, she hosted a holiday party with a guest list that included Gwyneth Paltrow  and Robert Downey Jr ., and she revealed a few tidbits about the event in her recent interview with Parade magazine . Jennifer traded hostess duties to be a guest in December, too, when she made an appearance at Emily Blunt's baby shower !