The pair, whose relationship reportedly became "strained" last year when Jennifer moved in with her fiancé, Justin Theroux, were spotted soaking up the sun in Cabo San Lucas, Mexico together on Saturday (28.12.13), after jetting there with a large group of mutual friends to ring in the New Year on Tuesday (31.12.13).
Justin, US chat show host Jimmy Kimmel, and outspoken radio star Howard Stern were among the other celebrities spotted hanging out with the former 'Friends' stars, according to the MailOnline website.
The New Year's holiday marks the third celebration Courteney and Jennifer are spending together in recent months.
The 'Cougar Town' actress, 49, also attended Jennifer and Justin's annual Christmas party earlier this month and a Thanksgiving bash at their home in Bel Air, Los Angeles in November, with her new boyfriend, Snow Patrol musician Johnny McDaid.
But Courteney was noticeably absent from the 'We're the Millers' star's birthday party for Justin in August.
A source previously claimed that the duo, who had been inseparable since meeting at the 'Friends' audition in 1994, were no longer as close because of Justin.
The insider said: "Jennifer's priorities have obviously changed since meeting Justin."
Courteney, who supported Jennifer through her 2005 divorce from Brad Pitt, allegedly felt "neglected" by Jennifer after she split from her own ex-husband David Arquette in 2010, with whom she has a nine-year-old daughter Coco.
The source added: "Courteney must feel that Jen has completely forgotten what it's like to be the single girl and that will hurt given how supportive she and David were to Jen over the years."
It was recently reported that Courteney is trying to get Jennifer to reunite with their former castmates for a 'Friends' reunion.