Grease is one of the most iconic films ever made. It was first released in 1978, and decades later, the movie is still as celebrated as it ever was. It starred the likes of John Travolta, Olivia Newton-John, and Stockard Channing. It gave us songs like Grease Lightning, Sandy, and You're The One That I Want.

While Grease beat the odds with its small budget of $6,000,000 and catapulted some of its stars to mega-fame, not everything that happened during filming was roses & sunshine. Here are twenty things that happened on the set of Grease that surprised even us.

20 John Travolta Tried To Heal The Director's Foot With His Religious Beliefs

During the filming of Grease, director Randal Kleiser fell very ill after his foot became infected. He showed up to the scene at the diner with a fever of 101 degrees. Travolta, who was very devout in his unconventional religious beliefs, thought that he could heal the director's foot. Randy did get better, but that might have been thanks to modern medicine.

19 Cha Cha Endured A Pregnancy Loss That Sent Her Straight To The Hospital

Annette Charles played Cha Cha, and she is probably best known for her flag-waving roll in the infamous car race scene. What fans of the film don't know is that Charles was enduring a pretty painful health issue while the scene was being filmed. She was in so much pain from an ectopic pregnancy that she had to lean against vehicles to get through the shoot.

18 Stockard Channing's "Love Bites" Were The Real Deal

We all remember the scene where Stockard Channing's character Rizzo does a full out inspection of her love bites in the mirror. What many people don't know is those love bites were not put there with makeup. They were put there by Channing's costar and movie love interest, Jeff Conaway. Talk about authenticity.

17 Jack Nicholson And Warren Beatty Worked Near The Set And Found The Cast Bothersome

Everybody loves the cast of Grease– almost everybody, that is. Rumor has it, Jack Nicholson and Warren Beatty were among those who counted themselves as non-fans. Their offices overlooked filming, and the cast was known to be so loud that the movie stars could not think straight and get their work done.

16 They Had To Blur A Poster Because It Showed A Coca Cola Logo (They Were Partnered With Pepsi)

Even the biggest Grease lovers probably missed the diner snafu where Sandy and her date are seen chatting it up over milkshakes and under a blurred out sign. The reason for the blurry sign is it sported the Coca Cola logo, and Grease was already in a partnership with Pepsi.

15 The High School Dance Scene Was Filmed Under Such Hot Conditions That People Started Getting Sick

Grease gave us the ultimate dance moves during the Prom scene in the school gym. The actors jived and gyrated to the tunes until they dropped... literally dropped. The temperatures were so high in the Huntington Park High School gym where they were filming that extras were becoming sick from heat-related illness.

14 Jeff Conaway's Issues With Addiction Started On The Set Of Grease

Actor Jeff Conaway was dropped by another actor while filming scenes for "Grease Lightning." Because of his injuries, he started taking painkillers while on set. His need for pills lasted a lot longer than the film did. He struggled with addiction until his untimely passing at age sixty.

13 Jeff Conaway Was Supposed To Lead Grease Lightning But John Travolta Insisted It Be Him

Jeff Conaway was supposed to head up the famous song, Grease Lightning, but Travolta insisted that he should be the lead on the song. Since John was big news at the time, having just filmed Saturday Night Fever, he got the part, and Conaway had to take a backseat to Mr. Big Shot.

12 Travolta Made A Stink Over A Close Up Of Him In The Song Sandy

When John Travolta belted out the tune of Sandy, he made hearts swoon from coast to coast. At the end of the song, Travolta lobbied for a close up of his beautiful face, but the director of the movie stuck to his gut and decided to go with the hot dog and bun scene. John wasn't thrilled, but it all worked out in the end.

11 The Water In The Race Car Scene Was Contaminated And Made Cast Members Sick

You would think that the scene that had the actors racing through watery roadways would have been dangerous because of speeding vehicles. It turned out hazardous for another reason, though. The water in the road was contaminated and ended up making some of the actors ill.

10 Because Travolta Was The Lead, Other Actors Who Were Taller Were Forced To Slouch Down

The masterminds behind Grease wanted the leading man, John Travolta, to stand taller than the other males in the film. Jeff Conaway, who naturally stands taller than Travolta, was instructed to slouch down for scenes where he stood next to John. That could not have been a huge ego boost.

9 Everything From Song Lyrics To Costumes Was Pushing The Envelope Back In The 70s

The lyrics, lines, outfits, and innuendos in the movie Grease seem pretty tame, especially compared to what we hear on the radio and see on television nowadays. Back in the seventies, Grease was really pushing the envelope and was considered to be pretty taboo. My how the times have changed.

8 Conaway Had It Bad For Olivia Newton-John, But She Set Him Up With Her Sister!

Jeff Conaway had a thing for his co-star, actress Olivia Newton-John, during the filming of Grease. While she liked him perfectly well as a friend, she was not interested in him in a romantic sense. She ended up introducing him to her sister, who Conaway eventually married. So technically Newton-John and Conaway were brother and sister for a few years in the eighties.

7 Conaway Got Really Friendly With Several Women On Set

Hook-ups between co-stars is nothing new and has been going on since the conception of Hollywood and the entertainment industry. Conaway capitalized on his role as one of the main characters and entertained several female actresses in his trailer. While other actors stuck to themselves, Conaway was ever the lady-pleaser.

6 Travolta Was In Mourning Over The Loss Of His Girlfriend, Diana Hyland, During Filming

While Jeff Conaway was living his best life and hooking up with actresses during the filming of Grease, his co-star, John Travolta, was doing the exact opposite. Travolta had very recently lost his girlfriend Diana Hyland and was said to be in a state of mourning while Grease filmed.

5 Director Kleiser Needed Pull From Travolta To Land His Directorial Role

Director Randal Kleiser had never done a film before heading up Grease, so when it came time for him to take the role of director on, he needed a little help from his old pal, Mega-star John Travolta. Travolta and Kleiser had previously worked together on Boy in the Plastic Bubble, so he could vouch for Kleiser.

4 No Teens Here, Only Adults Playing Young Roles

The movie Grease centers around a bunch of teenagers, but the main characters in the film were anything but. Most of the leading actors and actresses were well into their twenties and thirties when filming took place. Actress Stockard Channing was the oldest main cast member at thirty-three years of age.

3 Travolta Had A Major Ego

Before Grease, John Travolta had just hit it big with his feature acting role in Saturday Night Fever. His hip-shaking dance moves sent him right to the top of the industry. Travolta was the "it" guy, and he knew it. He was rumored to have had quite the ego during the filming of Grease.

2 Olivia Newton-John Had To Be Cut Out Of Her Iconic Leather Pants

Actress Olivia Newton John's black leather pants are almost as famous as the movie itself. Those pants were no joke, though. Newton-John had to be sewn into them before filming, and then the pants had to be ripped off at the end of filming. We are going to guess that she didn't do a whole lot of sitting while sporting those pants of hers.

1 The Director Didn't Like The Opening Song To The Film

After the original song to Grease was left on the cutting room floor, singer Barry Gibb was brought in to breathe new life into it. Randal Kleiser didn't love what Gibb wrote, thinking it was too dark for the film. He asked for it to be changed, but the song stayed and eventually became a huge hit.

Sources: Ranker.com, pensandpatrons.com, foxnews.com, bustle.com