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12 It's Always Sunny In Philadelphia Guest Stars You May Have Forgotten About

Kaitlin Olson, Rob McElhenney, Charlie Day, Danny DeVito, and Glenn Howerton

It’s Always Sunny in Philadelphia’s cast chemistry drives the series. Rob McElhenney, Glenn Howerton, Kaitlin Olson, Danny DeVito, and Charlie Day’s alluring dynamic has helped It’s Always Sunny in Philadelphia remain on the air and leave a legacy that continues to grow. It’s Always Sunny in Philadelphia's supporting cast of recurring characters and actors are equally ridiculous and exciting to watch. The McPoyles, Cricket (David Hornsby), The Lawyer (Brian Unger), Artemis (Artemis Pebdani) and many more have become part of the show’s DNA and its winning formula.

The It’s Always Sunny in Philadelphia cast and crew have had a wide range of guest stars over the years . The series has featured comedians, actors, directors, show runners, and musicians. These guest stars have seamlessly inserted themselves into the crazy shenanigans of the gang, as either themselves or some character that makes sense for their real life persona. With so many guest stars, there may have been a few that you’ve forgotten. Here’s a bit of a reminder.

Kaitlin Olson and Josh Groban in It's Always Sunny in Philadelphia

Josh Groban (Season 9, Episode 6)

Josh Groban made his claim to fame with his huge vocal presence, singing classic music, along with adult contemporary, jazz, and soft rock. He has multi-platinum albums, Grammy nominations, and Billboard Music Awards. Josh Groban is also no stranger to acting. He made guest appearances on various different comedy series, like The Crazy Ones and The Office, and he was co-lead on Netflix’s short lived The Good Cop.

Prior to his It’s Always Sunny in Philadelphia guest appearance episode, Dee (Kaitlin Olson) and Artemis mentioned that they are huge Josh Groban fans, Grobanites one might say. In It’s Always Sunny in Philadelphia Season 9, Episode 6, “The Gang Saves the Day,” the gang hides out during a convenience store robbery. They each begin to imagine what would happen if they actually tried to stop the robbery. In Dee’s vision, she kills everyone, but goes into the witness protection program where she gets a starring role on a TV show as a male British butler. Her new fame brings Josh Groban and her together. They marry, but unfortunately, she divorces Josh Groban to marry Brad Pitt. In his brief cameo, Josh Groban sings a song that references the many insults that Dee hears frequently from the gang.

P-Diddy on It's Always Sunny in Philadelphia as Dr. Jinx

Sean “P-Diddy” Combs (Season 8, Episode 6)

Sean “P-Diddy” Combs raps, sings, and produces. He’s worked with big names like Usher, Faith Evans, Biggie Smalls, and Mary J. Blige. His most famous hit singles include “I’ll Be Missing You” and “It’s All About the Benjamins.” P-Diddy also appeared on the screen in movies such as Monster’s Ball, Get Him to the Greek, and Muppets Most Wanted.

In It’s Always Sunny in Philadelphia Season 8, Episode 6 “Charlie’s Mom Has Cancer,” Diddy plays a shady man claiming to be a doctor. He goes by the name Dr. Jinx. He claims that he can use natural remedies to cure Charlie’s mom's cancer. The episode features a very funny stare-off scene between Dr. Jinx and Dennis (Glenn Howerton). He tries to cure Dennis’ inability to feel emotions by playing him a soulful guitar version of New Kids On the Block’s “You Got It (The Right Stuff).”

Paul Walter Hauser in It's Always Sunny in Philadelphia Season 6

Paul Walter Hauser (Season 6, Episode 9)

Last year, Paul Walter Hauser had his breakout role as Richard Jewell in Richard Jewell. He’s also appeared in Cobra Kai, Late Night, Kingdom, and I, Tonya.

Paul Walter Hauser appeared in one of the best episodes of It’s Always Sunny in Philadelphia Season 6. In Episode 9, “Dee Reynolds: Shaping America’s Youth,” Dee and Charlie (Charlie Day) get jobs working for a high school, Dee as a substitute teacher and Charlie as a janitor. This episode features the gang’s version of Lethal Weapon 5. Charlie bonds with Richie (Paul Walter Hauser), a kid who dresses as a Juggalo, the name for fans of the Insane Clown Posse. After seeing the gang’s Lethal Weapon 5, Richie drops the Juggalo makeup and starts wearing blackface, which of course ends in Dee and Charlie being fired.

Guillermo del Toro as Poppy McPoyle in It's Always Sunny in Philadelphia

Guillermo del Toro (Season 8, Episode 3)

Guillermo del Toro is a filmmaker, best known for Pan’s Labyrinth, Hellboy II: The Golden Army, Pacific Rim, Crimson Peak, and the Academy Award winning Best Picture The Shape of Water. Guillermo del Toro worked with Charlie Day on Pacific Rim, which likely led to this inspired It’s Always Sunny in Philadelphia cameo.

Guillermo del Toro appeared in two episodes of It’s Always Sunny in Philadelphia. The first in Season 8, Episode 3, “The Maureen Ponderosa Wedding Massacre,” and the second in Season 11, Episode 7, “McPoyle vs. Ponderosa: The Trial of the Century.” In both episodes, he plays Pappy McPoyle, a member of the infamous McPoyle incest loving clan. In “McPoyle vs. Ponderosa: The Trial of the Century,” he plays the key witness that allows Charlie to use bird law and win his case.

Oscar Nunez and Roger Bart in It's Always Sunny in Philadelphia Season 9

Oscar Nunez (Season 9, Episode 3)

The Office fans best recognize Oscar Nunez for his role as Oscar Martinez on the hit NBC series. He’s also made appearances on Mr. Iglesias, 3Below: Tales of Arcadia, and People of Earth. Oscar Nunez movie appearances include Baywatch, The Proposal, and The Italian Job.

Oscar Nunez appeared in It’s Always Sunny in Philadelphia Season 9, Episode 3, “The Gang Tries Desperately to Win an Award.” The entire episode is commentary on how It’s Always Sunny in Philadelphia gets ignored by major award shows, like the Emmys. In it, Nunez plays the manager of a bar name Sudz, a bar that receives many awards. Oscar Nunez’ appearance is a nod to shows, like The Office, that fit more into the award show standards. It’s a very layered, hilarious, and top-notch episode, which proves why it’s ridiculous that the Emmys ignore the series every year.

Retta on It's Always Sunny in Philadelphia

Retta (Season 4, Episode 12)

Retta played Donna Meagle on Parks and Recreation for the series’ seven seasons. She also appeared on Girlfriends’ Guide to Divorce for several seasons, and now plays Ruby Hill on Good Girls. She also had a role in the comedy Good Boys.

Retta had a very small role on It’s Always Sunny in Philadelphia Season 4, Episode 12, “The Gang Gets Extreme: Home Makeover Edition.” The gang kidnaps the Juarez family, and then forces them to participate in an extreme makeover of their lives and home. Retta plays the hardware store clerk that hears Charlie and Dennis discussing their questionable plans for their renovations. She doesn’t say much, but her facial reactions say it all.

D.B Weiss and David Benioff in It's Always Sunny in Philadelphia Season 12

David Benioff And D.B. Weiss (Season 12, Episode 2)

David Benioff and D.B Weiss are the showrunners of Game of Thrones. The men are huge fans of It’s Always Sunny in Philadelphia, and the It's Always Sunny cast are huge fans of Game of Thrones, which has resulted in the series’ stars doing crossover work. Rob McElhenney appeared on a Game of Thrones episode as an extra, and David Benioff and D.B Weiss wrote It’s Always Sunny in Philadelphia Season 9, Episode 8, “Flowers for Charlie.”

D.B Weiss and David Benioff returned to the It’s Always Sunny in Philadelphia world in Season 12, Episode 2, “The Gang Goes to a Water Park.” The gang engages in separate disasters: Dennis training a little girl to be a good con artist, Dee and Mac trapped in a water slide, and Charlie and Frank (Danny DeVito) pretend Frank has AIDS to allow them to skip lines. D.B Weiss and David Benioff play two lifeguards who have no interest in actually trying to save lives and stop the gang’s madness. It leads to chaos and death, something we’re sure Benioff and Weiss have become familiar with from Game of Thrones.

Chad L. Coleman as Z in It's Always Sunny in Philadelphia

Chad L. Coleman (Season 6, Episode 10)

Chad L. Coleman has appeared in the series All American, Interrogation, The Expanse, The Orville, and Arrow. Many know him best for his role on The Walking Dead, where he played Tyreese for a few seasons, and The Wire, where he played Dennis “Cutty” Wise.

Chad L. Coleman plays the recurring character Z on It’s Always Sunny in Philadelphia. His first appearance was in Season 6, Episode 10, “Charlie Kelly: King of the Rats,” and his most recent was in Season 14, Episode 9, “A Woman’s Right to Chop.” Z has appeared in five episodes of It’s Always Sunny in Philadelphia so far. He's one of Charlie and Frank’s bridge people friends. His funniest moments are when he’s just reacting to the ridiculousness of the gang. He usually responds to their extreme behavior with understanding and amusement.

Sinbad and Rob Thomas in It's Always Sunny in Philadelphia Season 4

Sinbad And Rob Thomas (Season 4, Episode 9)

Sinbad is a comedian and actor. His film gigs include Jingle All the Way, Necessary Roughness, First Kid, but not Shazaam. Sinbad has also had television roles in Rel, A Different World, and Steven Universe. Rob Thomas is the front man for Matchbox Twenty. A few of the band’s hits include “3AM,” “Unwell,” “If You’re Gone,” and “Lonely No More.”

Sinbad and Rob Thomas appeared together in It’s Always Sunny in Philadelphia Season 4, Episode 9, “Dennis Reynolds: An Erotic Life.” Dennis’ quest to publish an erotic memoir leads to him in a rehab. Rob Thomas and Sinbad, playing themselves, just happen to also be in this rehab and they’re borderline deranged bullies. Rob Thomas and Sinbad are hilarious in this random cameo combination.

Pablo Schreiber in It's Always Sunny in Philadelphia

Pablo Schreiber (Season 6, Episode 13)

You may know Pablo Schreiber for his roles in The Wire, Law and Order: SVU, Weeds, and Orange is the New Black. He played Pornstache on Orange is the New Black, and serial rapist and killer William Lewis in Law and Order: SVU. Pablo Schreiber also played Mad Sweeney on American Gods. He was recently cast as Master Chief John-117 in the Halo series adaptation. His movie roles include Den of Thieves, First Man, and Skyscraper.

It’s Always Sunny in Philadelphia Season 6, Episode 13, “A Very Sunny Christmas,” the gang recounts their Christmases. While telling Charlie about his Christmases of the past, Mac realizes that he and his family used to rob other people’s homes on Christmas. Charlie and he try to make it up to Pablo Schreiber’s character Ricky by trying to buy his children the hottest toy of that year. Things go very far off course, leading to an assault on a mall Santa.

The first thirteen seasons of It’s Always Sunny in Philadelphia are available to stream on Hulu. It’s Always Sunny in Philadelphia Season 14 should be available on Hulu in March. Stream it HERE (opens in new tab).

Jerrica Tisdale
Jerrica Tisdale

Spent most of my life in various parts of Illinois, including attending college in Evanston. I have been a life long lover of pop culture, especially television, turned that passion into writing about all things entertainment related. When I'm not writing about pop culture, I can be found channeling Gordon Ramsay by kicking people out the kitchen.