The former co-stars, who played Rachel Green, Monica Geller and Phoebe Buffay on the NBC series, enjoyed a girls night Sunday.
Cox shared a photo on Instagram with Aniston and Kudrow. The picture shows the trio putting their heads together as they pose for the camera.
"Trying to figure out what to say on Instagram....#gotnothing #friends #girlsnight," Cox captioned the post.
"Halfway there... #girlsnight #?" Kudrow wrote.
Aniston, Cox and Kudrow also reunited at Cox's 55th birthday party June 15. Cox shared a photo with the pair from the celebration.
"How lucky am I to celebrate my birthday with these two??? I love you girls. So much," she wrote.
"I would do it! The girls would do it, and the boys would do it, I'm sure," the star said. "Anything can happen."
Friends had a 10-season run on NBC from 1994 to 2004. Aniston previously discussed a reunion on The Ellen DeGeneres Show in February 2018, saying, "Anything is a possibility."