'Grease' casting director responds to criticism that the actors were 'too old' to play high-schoolers: 'It's a fantasy'

• "Grease" premiered in 1978, just about 45 years ago, and became a seminal musical adaptation.
• Casting director Joel Thurm spoke about the stars' ages in an oral history by The Guardian.

Nearly 45 years ago, the hit musical "Grease" premiered in theaters and quickly became a classic high-school-based love story. In a new oral history of how the movie came together and became a hit, the film's casting director addressed the oft-discussed age difference between the actors and the teenage characters.

"People might say the cast is too old, but Grease is not a documentary; it's a fantasy," Joel Thurm told The Guardian. "It is a non-PC fairytale that is better for the cast not being teens. The only thing that was important was that the cast all looked about the same age as each other, which they did."

Thurm said he had first met John Travolta when the young actor was just 17 years old. About six years later, Travolta signed on to make "Grease" at age 23 — and he was one of the youngest people on set who was playing a teenager in high school.

Costar Stockard Channing was 33, and Olivia Newton-John turned 29 during the movie's filming. Many of their castmates were in their late 20s and early 30s, too.

When Thurm references the "non-PC" aspects of the story, he's likely alluding to the subplots about sex and pregnancy and abortion, along with drinking and assault. Though some TV shows and movies tackle mature storylines with actual teen actors, Hollywood has long leaned towards casting stars in their 20s instead of actual adolescents for many projects.

For more on "Grease," read our breakdown of 17 cool things you probably didn't know about the movie-musical here.