“There Are Worse Things I Could Do” than cast older actors to play teens, argues the casting director behind “Grease.”

“Grease” hit the theaters in 1978 and it became an instant cult classic. However, despite the eye-catching ’50s costumes and infectious music numbers, one thing always stood out to audiences: the actors’ ages.

Casting director Joel Thurm got candid recently for the film’s 45th anniversary about how many have criticized him for casting adult-aged stars to play teens at Rydell High School.

“People might say the cast is too old, but ‘Grease’ is not a documentary; it’s a fantasy,” Thurm told The Guardian in an oral history for the movie recently.

“It is a non-PC fairytale that is better for the cast not being teens,” the filmmaker went on. “The only thing that was important was that the cast all looked about the same age as each other, which they did.”

Star John Travolta — who played ladies’ man Danny Zuko — was 23 when he signed on for the flick.

He may be one of the youngest people in the cast, but he was still a guy in his early ’20s playing a 17-year-old.

Stockard Channing, who portrayed headstrong Pink Lady Betty Rizzo, was 33 when she was hired.

The late Olivia Newton-John was 29 when she played Sandy Olsson, the film’s female lead. The supporting cast was also in their late 20s and 30s during the film.

Thurm revealed that it was Travolta, now 69, who wanted the Australian native for the role of Sandy.

“Unusually for a star like Olivia, she asked for a screen test because she was a singer, not an actor, and she was unsure about being quite a bit older than John,” he told the publication.

He explained that the crew set up a full film test of the drive-in scene and “she was perfect.”

Thurm went on: “She was so good that I didn’t have a backup Sandy – if Olivia had said no, you’d see me in the film in a skirt and a blond wig!”

And despite Channing, now 79, seemingly being too old and too culturally different from Rizzo to play her, Thurm confessed that she “mesmerized” everyone in the audition room and they “knew it had to be her.”

“Stockard could not have been more wrong as a person for Rizzo – she was well-born and wealthy and her manner of speech was totally different,” he said.

Thurm added that he knew without a doubt that the movie was “going to be a hit.” He explained that there was a 1950s revival going on in the pop culture at the time, especially with the debut of the sitcom “Happy Days” in 1974.

“The timing was right,” he pointed out. “The critics didn’t matter, since they forgot that audiences go to movies to have fun.”

In addition to giving stellar performances, the stars of the film had palpable chemistry and a lifelong friendship.

Newton-John died in August 2022 after a battle with breast cancer, but she had maintained a friendship with Travolta since their “Grease” days until her passing.

In her 2018 autobiography “Don’t Stop Believin,’” she wrote about how they had an “undeniable attraction” towards each other but they never acted on their impulses.

“Yes, we really liked each other and there was an attraction, but we would never date because we were both involved with other people at the time,” she penned. “Both of us have a loyalty streak that runs deep,”