People are freaking out over Monica's stand-in on Friends

The beloved TV show Friends may have ended over 10 years ago, but fans continue to watch -- and closely at that. One fan spotted something very interesting while rewatching, and couldn't help but share it with the world.

Twitter user and writer Nick Pettigrew posted a video of a stand-in for Monica who did not look like actress Courteney Cox who played her:

"I must've seen every Friends episode a million times," he said, "and never noticed the world's worst stand in for Monica."

How much money did the Friends cast make?

This is Courteney Cox, the "real" Monica:

Credit: Twitter

This is the stand-in, "fake" Monica:

Credit: Twitter

This is not the first time fans noticed an odd stand-in. This video catches one for Jennifer Aniston's Rachel:

Fans were shocked and the tweet went viral, generating hundreds of likes and retweets.

Why are viewers only just now realizing that sometimes, the Friends are not really the actual "friends"? It's because the show was never meant to be seen in widescreen; Cambio points out that in the 4:3 aspect ratio -- which was the standard when the show was airing -- these errors go unnoticed.