The Cast Member Family Cameo You Didn't Notice In It's Always Sunny
It's Always Sunny in Philadelphia premiered in 2005 and has been running strong ever since. The premise centers around a group of narcissistic friends who run a pub in South Philadelphia, Pennsylvania. The show's following is so strong, that in 2020 FX announced the show was renewed for four more seasons. The renewal means It's Always Sunny has set a new record as the longest-running sitcom, taking down the 1950's sitcom, The Adventures of Ozzie and Harriet (via Deadline).
The show was created by its stars Rob McElhenney, Glenn Howerton, and Charlie Day and has always been kept as a family affair, on and off-screen. Day's wife, Mary Elizabeth Ellis plays Charlie's on-screen love interest. While Emmy nominee Kaitlin Olson plays Dennis' (Howerton) sister Dee Reynolds. She married McElhenney in 2008. There's yet another, lesser-known family tie that breaks the fourth wall of "The Gang's" dingy Philly bar. Danny Devito, who plays tiny lunatic Frank Reynolds (Dee and Dennis's legal father), also has a close relative making appearances in the show.
Danny Devito's daughter is also in It's Always Sunny
Lucy Chet Devito, the daughter of Devito and Cheers actress Rhea Perlman, has made two cameos in the show to date (via IMDb). The first is in season two's "Mac Bangs Dennis' Mom." In the scene, Frank eyes his waitress, Jenny, played by his daughter, Lucy, after commenting that his date is too old for him. Lucy is billed as having a third appearance in the season two finale but doesn't appear on-screen.
So far her biggest role in the show came in season three's "Dumpster Baby", as a young woman who comments that the baby Mac and Dee found in a dumpster is cute enough to be a Gerber baby, prompting the pair to pursue a modeling career for the infant.
Taking after her thespian parents, Lucy is a film and television actress. She's starred in Disney's Melissa and Joey, appeared in The Marvelous Mrs. Maisel as Irene, and is set to appear in the upcoming film based on Marilyn Monroe's life, Blonde, alongside Ana de Armas and Adrien Brody.