The Familial Cameo In Always Sunny Season 16 A Lot Of Viewers Didn't Catch

The gang on "It's Always Sunny in Philadelphia" are a pretty tight-knit group with a long, complicated family history. At some point or another, most of the gang have claimed Frank (Danny DeVito) as their father, and Dee (Kaitlin Olson) and Dennis (Glenn Howerton) as twins. The cast have their own family connections too, as Olson is married to series creator and the man who plays Mac, Rob McElhenney, and the other guys have each had their spouses on the show! Charlie Day, who plays Charlie, is married to The Waitress (Mary Elizabeth Ellis), while Howerton's wife Jill Latiano made an appearance in season 5 and DeVito's wife Rhea Pearlman finally had a cameo in season 16. It's truly a family affair on "It's Always Sunny in Philadelphia," and in the latest season, another member of the extended "Sunny" family made his first appearance.

In "Risk E. Rat's Pizza and Amusement Center," the sixth episode of season 16, Olson and McElhenney's son, Leo McElhenney, got his chance to shine on the small screen in a short scene with DeVito's outlandish character Frank. It isn't the first family cameo on "It's Always Sunny" but it is a pretty funny one!

In the episode, the gang goes to Risk. E. Rat's, a kid-friendly entertainment center that's clearly riffing on the Chuck E. Cheese franchise, complete with animatronic singing characters, an arcade, and unfortunate souls in animal costumes who have to wrangle the hyperactive tots. The water fountain seems to be a bit of a problem for Frank, who uses a small cardboard fry tray to funnel water into his mouth. A child looks on and asks him what he's doing, and it's none other than Leo, Olson and McElhenney's younger son. He's also made an appearance as himself on McElhenney's series about the Welsh football team he bought, "Welcome to Wrexham," but it's fun to see him get a chance to test out his acting chops. With his incredibly talented and tuned-in parents, it wouldn't be a huge surprise if he follows them into the family business of entertainment.

Leo isn't the first McElhenney youngin' to make an appearance on "It's Always Sunny," though he is the first to do a bit of acting. After all, when his older brother Axel appeared on the show, he was a little too young to do much more than mug it up for the camera.

A decade or so and 10 seasons ago, way back in season 6, Olson and McElhenney's oldest son, Axel McElhenney, made his own cameo on "It's Always Sunny." He played the infant that Dee gave birth to in the episode "Dee Gives Birth," though Dee didn't keep the baby because she was a surrogate for Mac's transgender ex-girlfriend, Carmen (Brittany Daniel). Axel is just a tiny infant in the episode and hasn't gotten a chance to pop back in now that he's older, though he has also appeared on "Welcome to Wrexham."

The McElhenney boys aren't the only "Always Sunny" offspring to join their parents on the series, however. DeVito's daughter, Lucy DeVito, has appeared in two different episodes: "Mac Bangs Dennis' Mom" and "The Gang Finds a Dumpster Baby." In "Dumpster Baby," she has a quick line about the baby Dee and Mac found being "cute enough to be a Gerber baby," but the other appearance is a little creepier. In "Mac Bangs Dennis' Mom," Frank goes on a date and isn't interested because he thinks she's too old for him, and he checks out his waitress, played by none other than his daughter. Ew? Oh well, at least the DeVitos got to play father and daughter on the short-lived but hilarious and heartfelt cartoon series "Little Demon."

Season 17 is still a long ways away, but we can always hope for some more famous (and funny) family appearances. Leo was great in "Risk E. Rat's," so maybe it's time for the McElhenney brothers to show up together on the series set in the City of Brotherly Love...

You can check out "It's Always Sunny in Philadelphia" by streaming it on Hulu.