10 best one-time South Park guest stars

The ever-resourceful Trey Parker and Matt Stone know how to set their audience up for pleasant surprises. For 20 seasons and counting, South Park has admitted that it tends to for cheap imitations of household names.

The chief exceptions came in the formative seasons and the 1999 feature film, South Park: Bigger, Longer & Uncut. In those years, a smattering of celebrities did lend their real voices to the fledgling franchise.

Since then, Parker and Stone have enlisted A-listers with less frequency. The late Isaac Hayes remained a regular as Chef until 2006, and Bill Hader has logged 10 episodes, but those are the jutting anomalies.

The way the program now rolls in accordance with the claim that “all celebrity voices are impersonated…poorly,” viewers who came late to the party might be stunned by the guest spots from the ’90s and the year 2000.

With Comedy Central’s full-series marathon this week, fans who fall under that heading will have their chance to catch up. For those in need of a guide beforehand, here are the top 10 actors who appeared as themselves or as a one-off character in either one South Park episode or the movie. (For formality’s sake, be warned that many of the hyperlinked clips contain NSFW language.)

10. Mike Judge
As the mastermind behind Beavis and Butt-Head, Judge appropriately garnered a cameo (albeit uncredited) in the first theatrical film based on a controversial adult cartoon.

In the final scene of Bigger, Longer & Uncut, Kenny doffs his hood and speaks coherently onscreen for the first time. Between the steps onto that barrier and Judge’s role as Kenny’s voice, one could not have been blamed for thinking that would be the end of the South Park franchise altogether.

Not so much. Even so, as the climax of the movie, the moment was the culmination of a milestone. And who better than Judge to play the catalyst in that moment?

9-8. Tommy Chong and Cheech Marin
Declaring this comedic tandem from the ’70s inseparable would be an overstatement. With that said, when one is rating their allied appearances, they are hard to evaluate individually.

Accordingly, the brief Cheech and Chong revival for 2000’s “Cherokee Hair Tampons” occupies two slots on this leaderboard. With it, you had a four-time Grammy-nominated pairing reformulating their chemistry a quarter-century later.

7. Jonathan Katz
In 1998, Comedy Central crossed over its new series with the one for which Katz had nabbed a 1995 Emmy.

The network would have been practically remiss not to let this happen. The title character of Dr. Katz, Professional Therapist makes an impeccably placid foil to the irascible, defensive Mr. Garrison.

6. Malcolm McDowell
As both a live-action presenter and voiceover narrator, McDowell was the “British person” in a fourth-season Dickens parody.

Would it have been funnier if the storytelling “British person” were, say, one of the living Monty Python alums? Quite possibly, and it could have easily been arranged, as evidenced by another actor’s presence higher on this list. But McDowell brought a sound 36-year resume to the table for “Pip,” and he has hardly slowed down since.

5. Dave Foley
The former three-time Emmy nominee (shared with his castmates from The Kids in the Hall) was peaking in the late ’90s. NewsRadio was nearing a bittersweet close following the untimely death of Phil Hartman, and Foley had voiced the protagonist in Pixar’s sophomore movie, A Bug’s Life.

With those developments still fresh in the public’s memory, he took his talents to South Park: Bigger, Longer & Uncut to voice every Baldwin brother. Foley has kept plenty busy since then, and while he has not earned many front-and-center or hardware-caliber roles, that does not diminish his past output.

4. Eric Idle
For the movie, the former Python dropped in to play the scientist who designs an electroshock chip that deters blue language in children.

For viewers who did not know him before, Idle’s cameo readily illuminates his deft handling of silly lines. He — and, by extension, his character — makes no show of the two filthy phrases he has Cartman utter to test the device. He simply lets the humor sell itself, with the help of his native accent.

3. Minnie Driver
With the future star of ABC’s Speechless, Parker and Stone procured a rare instance of one A-lister impersonating another.

Coming off the acclaimed Good Will Hunting and Grosse Pointe Blank, Driver made voiceover roles the meat of her 1999. That summer, she was heard by countless theater-going families as Jane in the Disney adaptation of Tarzan.

Overlapping with that, her one-line impression of Brooke Shields in the South Park movie was tame compared to other content that had parents reeling.

2. George Clooney
“Big Gay Al’s Big Gay Boat Ride” was the fourth episode of South Park’s inaugural season. After the first three lived up to the disclaimer about celebrity impersonations — most notably Karri Turner as Kathie Lee Gifford — this one enlisted the show’s first familiar ringer.

In the middle of his breakout role on ER, Clooney took the time to bark on behalf of Stan’s gay dog, Sparky. With that, the show was halfway there toward including established talent in its mix.

Outside of the TV program, Clooney came back two years later for a more familiar role in the movie, voicing the ER surgeon who fails to save Kenny. Since he was allowed to speak a human language this time, this counts as his one appearance in the series for the purposes of this list.

1. Jennifer Aniston
Late in the fifth season of Friends, Aniston’s fame was still burgeoning at the time of this April 1999 episode. It had been six weeks since the release of Office Space, a film that, much like Aniston herself, accrued more appreciation in the next millennium.

In “Rainforest Schmainforest,” Aniston voices a choir teacher who takes the kids to the Central American wilderness. Her character’s championing of environmental protection makes her a natural foe for Cartman, and the episode unfolds accordingly.

Aniston’s highlight is her candid “You deserve to die” ruling when Cartman insists on going solo. Between the environment’s heat and humidity and Cartman’s unruly, unbecoming behavior, the only wonder is why she did not snap on him sooner.