20 Things You Didn't Know About It's Always Sunny In Philadelphia
10. Much Of Season 2 Was Shot Out Of Sequence
You'd never know it by watching, but much of the show's second season was actually filmed out of sequence, due to Danny DeVito only being available for 20 days of shooting.
As a result, the cast and crew were effectively working on all 10 episodes of the season at once, filming scenes from different episodes on the same day to accommodate DeVito.
Considering the cast were already uneasy about a major star joining their ranks, that change-up in production style must've been frustrating.
But again, it clearly didn't damage the quality of the episodes at all, and it's presumed that things returned to a more conventional shooting schedule from season three onward.