The photo saw Cox and castmates Lisa Kudrow, Jennifer Aniston, Matt LeBlanc, David Schwimmer and Matthew Perry sitting together on a private plane, with Cox revealing that the shot was taken before the show aired and made the six actors massive stars.
"The one where the six of us went to Vegas and no one knew we were F.R.I.E.N.D.S yet [throw back Thursday] [before it aired] [love these guys]," Cox wrote.
Her caption referenced the formatting of Friends' episode titles, which all begin with "The one where."
"This is TOO good !" Reese Witherspoon wrote, while former Dance Moms cast member Christi Lukasiak shared, "Oh. My. God. I read about this in the book Top of the Rock. Amazing to actually see it."
"Look at that! Thanks again Jimmy Burrows," Kudrow commented. "Love you Courteney."
Kudrow was referencing Friends director James Burrows, who previously told Vanity Fair that he had the cast take a trip to Las Vegas together after the show's pilot was filmed to have them get to know each other better.
"I had me and six of them [on the trip]," Burrows recalled. "And I said — I don't know why I said this — I said, 'This is your last shot at anonymity. Once the show comes on the air, you guys will never be able to go anywhere without being hounded.'"
"I knew the show had a chance to really take off," he added.
Burrows shared that after arriving on a private plane, the cast enjoyed dinner at Caesar's Palace before he sent them to the casinos.
"So I did that and then I said, 'Do you want to gamble?' and they said, 'Yes.' I said, 'Okay, go ahead,'" he said. "And all six of them didn't have any money so they each wrote me checks for $200 and I cashed them. And that was it. They came back and premiered and they don't have a shot of anonymity anymore."
Kudrow recently told Entertainment Tonight that the pilot was her favorite episode of Friends.
"The pilot. Just how thrilling that was," she said. "We were like little puppy dogs, just climbing all over each other and playing and playing games. It was fun."
Photo Credit: Getty / Michael Tran