It's been a little more than 15 years since Friends came to an end.

And while we'll always have a soft spot it our hearts for the sitcom, the ability to watch (and re-watch) our favourite episodes has resulted in eagle-eyed fans noticing a number of errors. Like the problem with Monica's wedding dress. Or the really creepy detail about Rachel's date with Joshua. Now, fans have uncovered another error in the sitcom - and we can't believe we never noticed it before, to be honest. One fan took to Reddit to point out the blunder, which took place in the season three episode, The One Without the Ski Trip - which takes place a week after Ross and Rachel's split. The former couple can't even stand being in the same room as each other, each blaming the other for their separation while their friends are caught in the middle as they try to keep them apart as much as possible. Rachel invites the gang (minus Ross) to her sister's cabin for a ski trip, which the guys agree to instead of a LaserDisc weekend marathon playing darts with Ross. The guys leave for the cabin but they have to pull in so that Chandler can go to a restroom. Rachel, however, closes the door of the cab, which has the keys locked inside. After plenty of arguing, they give in and decide to call Ross for help. After Ross gets Phoebe's cab ready to continue the journey ahead, the group try to figure out who is going with who - and a camera man can be spotted in the corner, just over Ross' shoulder. You can see the moment around the 1:58 mark in the clip below.  https://www.youtube.com/watch?time_continue=118&v=l51JIUSFetE