The 20th season of “South Park” is airing soon. Before watching the new adventures of Stan, Kyle, Eric and Kenny, enjoy some of these fun facts you might not have known about the show.

1. Each episode features a celebrity

It’s not a real “South Park” episode if there is no celebrity involved. You can bet that one will be included in an episode, whether it be a parody or simply a reference. There have been a lot of celebrities parodied on the show. There have also been many guest appearances, although the celebrities didn’t really appear as themselves. George Clooney was in an episode where he played a dog.

The only celebrities who have voiced themselves on the show are Jay Leno, Radiohead, Korn, Robert Smith, PewDiePie, Brad Paisley and Wing, according to Uproxx.

2. The “South Park” movie has the most swearing in an animated movie

“South Park: Bigger, Louder & Uncut” holds the Guinness Book of World Records’ title of “Most Swearing in an Animated Movie,” according to Entertainment Weekly. The 1999 film has 399 swear words.

3. The production for an episode takes only days

Unlike other animated series, which take months to produce, the hit from Trey Parker and Matt Stone only takes a few days to finish. This makes it easy for the show to include topics from current events.

4. The expression “derp” came from Stone and Parker

The expression, which people use in place of something foolish or stupid, was introduced during the 1999 episode “Suburb” when the new character Mr. Derp was introduced, according to New York magazine.

5. Stone and Parker used pseudonyms for the pilot

The original pilot, which ended up not being aired, bore Stone and Parker’s pseudonyms. Parker used Tupac Schwartz and Stone used M.C. Goldstein.

“South Park” Season 20 will premiere Sept. 14 at 10 p.m ET on Comedy Central.

South Park Here are some “South Park” facts you might not know. Photo: Comedy Central