On Thursday, December 12, the "Friends" star posed for a snap with comedian David Spade and former "The Bachelor" star Nick Viall, under which fans couldn't help but highlight the similarities between Cox and the former Olympic Gold Medallist when Spade shared it on his page.
Taking to the social networking site on Saturday, the actress shared a gallery of photos - the first showing the original image, followed by a screenshot of several of the comments posted by his followers.
"@davidspade posted this pic, now I really didn't think I looked like myself but this was surprising...." Cox captioned the post.
In the third and final slide, the star shared a collage of snaps of herself and Jenner, under which she conceded: "Alright... I can see it."
Weighing in on the discussion, Cox's pal Jennifer Aniston, who made her record-breaking debut on Instagram in October, couldn't help but laugh.
"You're hilarious," she commented under Cox's post. "Oh my GOD I love you."
Jenner has yet to respond to the post.