More than a decade after the sitcom aired, 'Friends' fans began to notice that Jennifer Aniston's stand-in had been mistakenly shown in two scenes

Friends fans might think they've seen it all, but did they see The One Where They Forget to Edit In Jennifer Aniston?

Friends ran for 10 seasons on NBC from 1994 to 2004. The beloved series starred Aniston (Rachel Green), Courteney Cox (Monica Geller), Lisa Kudrow (Phoebe Buffay), Matt LeBlanc (Joey Tribbiani), Matthew Perry (Chandler Bing) and David Schwimmer (Ross Geller) as a group of 20-somethings living in New York City.

Now, over a decade since the hit sitcom originally aired, one eagle-eyed fan spotted an editing mistake in season 9, episode 15, titled "The One With the Mugging" — and the discovery has gone viral.

In the scene, Rachel runs into Monica's apartment to inform Joey he landed an audition with a fictional A-list actor named Leonard Hayes, played by Jeff Goldblum. Once she shares the news, the camera pans to Joey, who appears to be standing next to "Rachel."

However, fans noticed it wasn't actually Aniston standing next to LeBlanc, but rather her stand-in.

Related: 'Friends' Cast Talks Off-Screen Crushes, On-Set Mishaps and More: 10 Revelations from the Reunion

This wasn't the first time an editing blunder made it into the final cut, either.

Earlier in episode 4 of the same season, titled "The One With the Sharks," loyal Friends fans spotted Rachel getting replaced by a stand-in actress 12 minutes and 20 seconds into the episode.

Monica and Rachel are sitting at a table when Joey walks in to join them. In the original shot, Rachel is seen wearing a yellow shirt with curly hair.

But when the camera eventually shifts towards Monica, the actress who is standing in as Rachel can be seen in the bottom left side of the screen wearing a blue top with straight hair.

After 17 years, the Friends cast got back together for the HBO Max special, Friends: The Reunion, in May 2021. During the special, the cast reminisced about how much the sitcom had meant to them in both their personal lives and their careers.

"It was an incredible time," Cox gushed with her costars. "Everything came together. We became best friends through just the chemistry, the whole thing. It was life-changing and it forever will be — not just for us, but for people who watch it, and that's such a great feeling to carry forever.

Related: There's a 'Friends' Central Perk Coffeehouse Opening — and It's Not in New York! (Exclusive)

Though Aniston was excited to reunite with her costars for the special, she admitted the experience was more "melancholy" than expected during an appearance on the Literally! With Rob Lowe podcast in September of that year.

"I think it really took us all down way harder than we anticipated," she admitted at the time. "Because in your mind, you think, 'Oh, this will be really fun to time travel.' It turns out, oh, ouch — it's kind of hard to time travel."