Little does she know, her summer fling, Danny Zuko, also goes to her new school.

While Sandy is a wholesome girl-next-door, Danny is one of the cool guys.

Most of us probably grew up watching this musical thinking that it showcased the epitome of high school life.

The cast of Grease

Re-watching the movie today, you’ll probably notice that these kids look a lot like well adults!

Here’s the low-down onhow old the actors ofGreasewerewhile filming.

While Newton-John definitely pulled off the innocent high school act, she was significantly older than her character.

Olivia Newton-John as Sandy

In fact, she was 29!

As she confessed toEntertainment Weekly, Newton-John initially thought she was too old to play Sandy.

“I was 29 and worried that I didn’t look young enough,” she recalled.

John Travolta in Grease

However, when she met John Travolta, who played Danny, she realized they were the perfect match.

“John and I had great chemistry from the first time we met,” she continued.

“We bonded forever on celluloid.”

Stockard Channing as Rizzo in Grease

And Travolta felt the same way in fact, it was his idea to cast her.

As he toldPeople, “They were desperately looking for a Sandy.”

However, at the time, he was just an up-and-coming star.

Jeff Conaway in Grease

He reportedly once told Jim Jacobs,Greaseco-author, “All Doodys dream of becoming Dannys someday.”

As co-star Didi Conn told theDaily Mail, “Oh, yeah [he did like her].

To that end, Channing toldBroadway World, she had to forget about her age to play Rizzo.

Barry Pearl in Grease

“I was so much older than she was in life,” she explained.

While Channing may have been 14 years too old, her age may have actually helped with her performance.

“I fought for it,” she added.

Michael Tucci in Grease

“It got in there by the skin of its teeth.”

Clearly, Channing’s age gave her the wisdom to know exactly what the movie needed!

Conaway, like many of his co-stars, was older than his character at the time; he was26.

Kelly Ward in Grease

According toPeople, Conaway was cast after being the understudy for Danny in the Broadway version ofGrease.

Funnily enough, Conaway returned toGreasein the 1994 Broadwayrevivalplaying Vince Fontaine.

“The trailer would be rocking at lunch,” she quipped.

Didi Conn in Grease

And as another co-star Barry Pearl toldThe Sun, “He made out like a bandit.”

As he later toldPeople, he wasn’t prepared for the fame.

“You’re thrown into the jaws of success and it’s a heavy thing,” he revealed.

Jamie Donnelly in Grease

Conaway was diagnosed with drug addiction and later, clinical depression.

Although he eventually turned things around, he sadly passed away in 2011 (viaThe New York Times).

Even though Pearl was older than his character, he loved the excuse to cut loose.

Dinah Manoff in Grease

Like some of the other cast members, he' played several roles in thestageversion ofGreasebefore getting cast.

Even though Tucci had experience with the producers, he wasn’t immediately cast inGrease.

Luckily, after seeing Tucci’s audition, his age was no longer an issue.

Susan Buckner in Grease

Tucci was thrilled to be cast inGrease.

As he said in an interview onKTLA 5, “It changed our lives.”

As Ward toldKTLA 5,doing the film was kind of like going back a few years.

Lorenzo Lamas in Grease

“We spent 15 very intense weeks together,” he explained.

“It was kind of like high school.”

Ward moved away from acting in his thirties when he realized he could no longer pass as a teen.

Annette Charles in Grease

As he toldAnimation Guild, he’d made his career by playing young characters.

Luckily, Ward was still young enough to play a teen inGrease!

It was important for regressing to those teenage years, but also for that spontaneous energy.”

Dennis Stewart in Grease

For Conn, Frenchy reminded her of herself when she was younger.

“I really wanted to start acting when I was young and my parents wouldn’t let me.”

Conn confirmed just how much fun theGreasecast had in an interview for theDaily Mail.

Eddie Deezen in Grease

At the wrap party, she said, they all got high!

Jamie Donnelly let her inner child come out filming Grease

Jamie Donnelly played the pigtailed Jan inGrease.

And even though Donnelly was playing a high schooler, she was 31 years old at the time.

Chances are Donnelly landed the role because of her work in the staged version ofGrease.

As she toldV13, “I had played Jan on Broadway seven years before I did the movie.”

Plus, Jan was an easy role for Donnelly to play, even if she was a little younger.

“Jan has a lot of who I am in her.”

“We’re still ridiculously childish I think,” she added.

Sounds like her youthful spirit made the age difference work.

In fact, Manoff was just 19 years old when she was cast.

As she toldThe Seattle Times, the actress was actually shocked to be in the film.

“I don’t know why they cast [me],” she said.

Of course, at 19 or 20, Manoff was still a little older than Marty.

Just like the rest of the cast ofGrease, Manoff had a ball on set.

As she toldThe Sun, she even developed a bit of a schoolgirl crush on John Travolta.

“He was radiating so much talent and energy.

I just started stuttering.”

In the film, she was played by Susan Buckner, who at the time was around25 years old.

As Buckner toldPeople, the whole cast definitely acted younger than their years.

“We were so bad,” she recalled.

“Almost everybody would come in two, three hours late.

They had to bring us all in and give us a lecture.”

AfterGrease,Buckner ended up directing children’s theater in Miami and raising two children.

She even directed a production ofGrease!

He played Tom, the all-American football player who briefly dated Sandy.

He was, according to Deezen, just 19 years old.

In fact, Deezen believed that Lamas was the only real teenager on theGreaseset!

In 2018, Lamas opened up about his time onGreasein an interview withStudio 10.

“So I was kind of in a complete zombie state to begin with.”

Sounds like a total dream for this young actor!

She’s the girl from the other high school who steals Danny’s attention at the school dance.

She’s also Leo’s girlfriend, whose iconic scarf starts the big car race.

Charles would have been around29at the time of filmingGrease.

Of course, having a slightly older actress made sense for this role.

The character of Leo was one of six who reappeared in the sequelGrease 2, according toIMDb.

Sadly, Stewart passed away from AIDS in 1994 when he was just 46 (viaThe Sun).

“I was barely 20,” he revealed.

As he explained, he actually had the “fewest lines of any actor inGreasewith a speaking role.”

His only two lines were “It’s Eugene,” and “Thank you.”

Apparently, Travolta would say, “Are you alright, buddy?”

after every take of the scene when the boys bully him.