Over the course of many very funny seasons, It’s Always Sunny in Philadelphia has transformed from an experimental, low budget comedy into one of the most original and popular shows on television. Distinctive, despicable and very sharp, there is no other comedy quite like It’s Always Sunny, largely due to the narcissism portrayed by the main characters. Being so unique, it also means that there are tons of brilliant facts about the show which give you much greater appreciation for its comedy and the production of the show. Here are 10 fascinating facts about the Paddy’s Pub crew.

10. The Show Has The Cheapest Opening Credits Ever

It’s Always Sunny in Philadelphia started out on a very low budget, with the pilot reportedly costing under $200 to make. The now-famous opening credits, which have been the same for 11 seasons, were particularly cheap to make, and are actually the cheapest ever used on TV. The credits simply show shots of streets and landmarks on Philadelphia, all of which were shot by the gang on a digital camera while driving around the city. This explains why some of the shots are out of focus and why it feels like a handheld camera was used, because, well, it was! Additionally, the catchy theme music is a public domain song, Heinz Kiessling’s “Temptation Sensation”. Although the show has changed and evolved over the years, it still retains the charm of a low budget comedy. This is a big part of its appeal, and what separates it from other shows.

9. The Cast Don’t Drink On Set

On the show, alcohol is regularly a major component of the plot, and the characters are shown to be poorly functioning alcoholics. Due to running their own bar, the gang has a constant supply of alcohol, which often fuels their wild schemes or ignites their constant arguing. It is rare for a beer bottle not to be in any shot, with each member regularly drinking regardless of the time of day. There are also episodes where alcohol is the main part of the story, such as “The Gang Beats Boggs”, where they attempt to drink 70 cans of beer on a cross country flight. However, during a Reddit AMA, Glenn Howerton (Dennis) revealed that the cast never drink on set and instead use substitute liquids to stand in for alcohol. Howerton added that drinking during filming was bad for insurance and that they did not want to put the show at risk. One thing is certain, with the amount of “beer” that they go through in the average episode, it would also be extremely expensive.

8. Charlie Writes Most Of The Songs Himself

Anyone who considers themselves a fan of the show will know that many of the highlights come from Charlie’s (Charlie Day) music. This includes the hilarious and extremely catchy song “Dayman”, which he later turned into a brilliant dramatic musical titled “The Nightman Cometh”. He also writes and performs a fantastic song during the episode “The Gang Tries Desperately to Win an Award”. Charlie is shown to be surprisingly artistic on the show (another layer to his strange character), but Charlie Day himself is also very talented in real life. He is shown to play the songs on TV, but he has also written and improvised plenty of the music featured on the show. Typically, the lyrical content in his songs is extremely bizarre and disturbing, which gives an insight into his obscure life. His musical talents are a key source of humor on the show (particularly the recurring Dayman/Nightman creation).

7. Danny DeVito Only Joined Because His Kids Were Fans

The polarizing humor found in the show from the very start meant that it was difficult to get off the ground, and it is said that it was close to cancellation after the very first season. In a bid to boost ratings, the network claimed that the show needed to bring in a star. Brilliantly, creator Rob McElhenney recruited none other than Danny DeVito, who joined in Season 2 as Frank Reynolds, father of Dennis and Dee. DeVito’s character has since gone on to become a fan favorite and is considered integral to the show’s success. However, it was DeVito’s children that should be credited with persuading the star to join the cast, as they were enormous fans of the show already. After coming on board, DeVito enjoyed being on the show so much that he quickly became a regular, joining the gang in all their wild schemes and plots, which would see the character of Frank gradually become more and more depraved.

6. The Original Premise Was Very Different

Originally, the show was set to be very different, and wasn’t even set in Philadelphia! The original pilot was titled It’s Always Sunny On TV and is set in Los Angeles, with the gang not running a bar but were instead struggling actors in the film industry. The pilot demonstrated similar humor and also some similar storylines, but ultimately it was shaping up to be a very different show to the one that we know and love today. The creators took the pilot to a number of networks before it was picked up by FX. In an addition fun fact, prior to the pilot getting made, McElhenney and Glenn Howerton first had a film idea about a man telling his friend he might have cancer, while the friend had really only come by to borrow a cup of sugar. This cringe-inducing tale was quickly incorporated into the show in Season 1 for the episode “Charlie Has Cancer”.

5. Guillermo Del Toro Cameos In Season 8

While shooting his role in Guillermo Del Toro’s film Pacific Rim, Charlie Day was approached by the popular director, who told him that he was a huge fan of the show and would love to be a guest star. Unsure on how true this statement was, after filming was complete, Day later emailed Del Toro, who confirmed that he was, in fact, serious, and they arranged for him to appear on the show. This would happen in the Season 8 episode “The Maureen Ponderosa Wedding Massacre”, where Del Toro briefly appears as gibberish-speaking Pappy McPoyle. He reprised this role in the Season 11, for the episode “McPoyle vs. Ponderosa: The Trial of the Century”. The extremely odd, depraved and incestuous McPoyle family has become fan favorites on the show who regularly appear and act as antagonists to the gang, most notably Ryan and Liam McPoyle, who went to school with Mac and Charlie.

4. The Game of Thrones Series Creators Wrote An Episode

In Season 9, the episode “Flowers for Charlie” was written by none other than David Benioff and D.B Weiss, who are best known for being the series creators of Game of Thrones. As huge fans of the show, they inquired about writing an episode as a change of pace from their normal duties in Westeros. The result was a very well-received episode, which was a parody of the book Flowers for Algernon. In the episode, Charlie becomes smarter after taking a pill (much like the movie and TV show Limitless), but this change in his character is not well-received by his friends. Elsewhere, the gang attempt to take on “Charlie work” by catching a rat, but end up getting high on gasoline. Interestingly, TV show The League (a show regularly compared to IASIP that also airs on FXX) released an episode the very same evening called “Flowers for Taco”, with a similar plot where Taco becomes smarter after giving up smoking weed.

3. Rob McElhenney Gained 50 Pounds Of Fat For Extra Humor

In a shocking moment in Season 7, Mac (Rob McElhenney) walked through the door to Paddy’s Pub to reveal that he had gained around 50 pounds of fat. This was not McElhenney letting himself go, but instead his plan to add extra humor to his character (he had also grown an impressive beard). McElhenney stated that this weight gain was his way of fighting the trend of actors getting more attractive as the show grows in success (most notably on The Big Bang Theory). In the show, Mac wanted to gain weight to become the same size of a bodybuilder and justified his constant snacking as “cultivating mass”. While it offered the show a new comedic direction, the extreme weight gain (and later loss) was actually extremely dangerous and the rest of the cast and crew were on the fence about it, with Charlie Day describing it as “disgusting”.

2. They Were Not Nominated For A Major Award Until 2013

Although it struggled with ratings early on, the show has since exploded in popularity, and the quality has been lauded by many, with some claiming it to be the funniest thing on television. And even though it has been setting such a high standard for around a decade, it was not nominated for a major award until 2013. Even then, the nomination was an Emmy for Outstanding Stunt Coordination for a Comedy Series or Variety Program, which they did not win. In a form of revenge, during Season 9, they poked fun at the Emmys with the episode “The Gang Tries Desperately to Win an Award”. In the episode, the gang is upset that they have never even been nominated for a “Best Bar in Philadelphia Award” and go to great lengths to try and win one. In a very self-aware episode, they attempt to be like the other bars, but in the end they realize that they cannot change who they really are.

1. There Are 3 Real Life Couples On The Show

Although the characters may make it seem otherwise, there is a lot of love on the show. Dee (Kaitlin Olson) is constantly ridiculed on the show, but in real life she is married to Rob McElhenney, who plays Mac, and is arguably Dee’s worst tormentor on the show). After hiring her to play Dee, Rob fell for Olson in Season 2, claiming that he found her to be the funniest woman in show business. They are now married and have 2 children. Another brilliant fact is that Charlie Day (Charlie Kelly) is married to Mary Elizabeth Ellis (The Waitress). On the show, Charlie is obsessed with Ellis’ character and follows her everywhere, much to her annoyance. The couple first met in real life after playing incestuous twins on Reno 911. Finally, Glenn Howerton (Dennis) is married to Jill Latiano, who guest starred in an episode where Dennis seduces her using his legendary “D.E.N.N.I.S System”.