It's Always Sunny in Philadelphia (also known as It's Always Sunny, Always Sunny, or just Sunny) is an American television sitcom created and developed by Rob McElhenney, Glenn Howerton, and Charlie Day. The series follows the exploits of "The Gang", a group of self-centered friends who run Paddy's Pub, an unsuccessful Irish bar in South Philadelphia.

The musical was written by Rob McElhenney (Mac), Charlie Day (Charlie) and Glenn Howerton (Dennis) who will be joined by Kaitlin Olson (Sweet Dee), Danny DeVito (Frank), Mary Elizabeth Ellis (The Waitress) and Artemis Pebdani (Artemis).