Since Tim Burton introduced the world to Jack Skellington” 25 years ago, “The Nightmare Before Christmas” movie and lead character have become synonymous with celebrating Halloween.

First released in 1993, the film follows the story of Jack Skellington, the “Pumpkin King” of Halloween Town, who grows tired of celebrating the annual holiday the same way each year. Eager to bring back fun to the special day, Jack discovers Christmas Town and believes he has found the answer to his dilemma.

His grand plan sends him on a wild adventure that has been enjoyed each Halloween by adults and children of all ages. While there are probably millions of people who have seen this movie more than once, there are still several facts others may have missed about this cult classic.

Thanks to information from IMDb, MousePlanet and the Los Angeles Times, we rounded up these 10 facts that you probably didn’t know about “The Nightmare Before Christmas” in honor of the movie's 25th anniversary.

1. Tim Burton Has Never Been Interested In Making A “Nightmare Before Christmas” Sequel.

However, a follow up to the popular movie has been released via comic-book. Burton previously revealed he felt a responsibility to preserve the authenticity of the Halloween film. “I was always very protective of [‘Nightmare’], not to do sequels or things of that kind. You know, ‘Jack visits Thanksgiving world’ or other kinds of things, just because I felt the movie had a purity to it and the people that like it,” Burton explained.

Fast forward to 2018, when Manga publisher Tokyopop released “Nightmare Before Christmas: Zero’s Journey.” The comic follows the story of Zero, Jack’s ghost dog that must get help from the residents of Christmas Town to find his way back to Halloween Town. The sequel is being released as 20 single issue comic books.

2. Jack Had Many Faces.

Around 800 different replaceable heads were made to ensure Jack could make a variety of facial expressions.

3. The Film Took Three Years To Make.

Each second of on-screen action required 24 different frames and potentially 24 distinct character movements. Due to the detailed attention required to make a stop-motion animation movie, the production crew completed no more than 70 seconds of film per week.

4. “The Nightmare Before Christmas” Actually Started Out As A Poem.

Burton first penned the classic in 1982, during his time as an animator for Walt Disney. Eleven years later, his holiday poem hit the big screen for the first time.

5. Getting Jack To Christmas Town Was A Difficult Task.

The hardest scene to film was Jack reaching for the doorknob to Christmas Town. In order to create a convincing image, the crew had to make sure Jack’s expressions, as well as the forest behind him, were perfectly reflected in the doorknob while keeping the camera and equipment out of the shot.

6. “The Nightmare Before Christmas” Was Almost A Television Series.

Prior to hitting the big screen and becoming a holiday classic, Burton initially pitched “The Nightmare Before Christmas” as a television special. Although the content was considered too grim to air on TV, the director refused to give up and eventually persuaded Disney to give the movie a chance.

7. Jack Was Designed Without Eyes For A Reason. 

Burton refused to compromise with Disney about adding eyes to the main character of the film. “The first rule of drawn animation is that you have to have eyes for expression,” Burton explained.

“I thought it would be great to give life to these characters that have no eyes. Disney really fought for us to give Jack these friendly eyes instead of dark holes but we wouldn’t budge.”

8. Jack’s Suit Was Initially Black.

Director Henry Selick revealed Burton’s original model of the character consisted of a black suit. However, there was a major concern that the outfit would blend into the background and disappear on screen. As a result, Selick added white stripes to create a pinstripe suit that would prevent the character’s body from disappearing on sets with dark backgrounds.

9. “The Nightmare Before Christmas” Has Made Movie History.

The flick is the first stop motion-animated film to be rated PG by the MPAA and it is also Walt Disney’s second fully animated film to carry the rating. The company’s first PG-rated production was the 1985 movie “The Black Cauldron.”

10. The Director Of The Movie Wasn’t Famous Enough To Have His Name In The Title.

Although the film was initially released as “Tim Burton’s The Nightmare Before Christmas,” Selick did most of the work. The director previously revealed Burton only spent a total of eight to 10 days working on the production of the movie.

“We did communicate while he was filming in Los Angeles and he offered suggestions. It’s more like he wrote a children’s book and gave it to us and we went from there. But the bottom line was that Tim Burton’s name before the title was going to bring in more people than mine would.”

The Nightmare Before Christmas Pictured: Perpetual trick-or-treaters: Lock, Shock and Barrel return triumphantly to Halloweentown with Santa Claus so Jack Skellington can take his place in Touchstone Pictures animated film, “Tim Burton’s The Nightmare Before Christmas.” Photo: Getty Images/Handout