Cox, 56, shared a quick video of herself with her two Friends co-stars that reads, "Friends don't let friends skip elections."
In the silent video, Aniston, 51, pulls Cox in close and whispers something in her ear as Kudrow nods. The video is captioned, "Text FRIENDS to 26797 to make sure you are registered. And tag your FRIENDS below to remind them to check their registration #RegisterAFriendDay @iamavoter."
Kudrow, 56, shared a sweet photo of the pals grinning together with the same caption. In the shot, Cox is wearing a beige blazer over a white shirt, Kudrow has on a black blouse, and Aniston is rocking a tan turtleneck sweater.
Aniston took to her Instagram Stories, sharing a meme of her Friends character, Rachel Green, gasping, with the words, "When you realize there are only 100 days until Election Day."
Other stars like Gwyneth Paltrow and Robert Downey Jr. also participated in the initiative, posting a cute FaceTime video between the Marvel co-stars and on-screen spouses, encouraging fans to register to vote.