Though Jennifer Aniston is perhaps best known for her turn as Rachel Green on bestsitcomever Friends, it might surprise you to learn that she was originally brought in as a potential choice to play the role of - would you believe it? - Monica Gellar. That's right: it was very much almost a thing that Aniston could have ended up playing sister to David Schwimmer's Ross instead of his all-time love interest. Weird, huh? Thankfully, things worked out a whole lot differently. In Aniston's own words:
"They wanted Courteney to play Rachel. And unbeknownst to each other, I wanted to play Rachel and she wanted to play Monica. It worked out perfectly."
Phew. It's hard to imagine it any other way, to be perfectly honest.