Once upon a time in Hollywood — 25 years ago, as a matter of fact — the former teen idol and one-time box office king John Travolta revived his career in spectacular fashion with his Oscar-nominated performance as Vincent Vega in Quentin Tarantino’s “Pulp Fiction.”

But unlike Brad Pitt, Leonardo DiCaprio, Samuel L. Jackson, Bruce Dern, Harvey Keitel, Michael Madsen, Kurt Russell, Tim Roth, Christoph Waltz, Uma Thurman, et al., Travolta has yet to join the ranks of Tarantino regulars who have made multiple appearances in QT films.

There’s even a “Reservoir Dogs” shout-out in Travolta’s new movie “The Fanatic,” which he was promoting during a recent visit to Chicago.

So why haven’t we seen Travolta in any Tarantino films of the last quarter-century?

“You know, Quentin was ‘The Fanatic’ about me when we first met,” said Travolta with a chuckle. “So I know how he feels about me. And he’s a man of his own destiny. If he feels there’s something that’s [right for me], we’ll do it.

“Don’t forget, at one point it was Michael Madsen who was going to do ‘Pulp Fiction.’ But [Tarantino] changed on a dime and said, ‘I can’t get John out of my head for Vincent.’

“I don’t interfere — my feeling is, if Quentin wanted me to be in a movie of his, I would be, because I know his love is pure. But even when I look back, what WOULD I have done in one of his movies? Because nothing would be as special as Vincent. …

“I mean, I probably could have done, maybe Brad’s part in ‘Once Upon a Time [in Hollywood],’ but there was something about Brad’s vibe with Leo in ‘Once Upon a Time …” that I loved.

“Nothing’s going to really beat ‘Pulp Fiction,’ for his work, and it’s an icon for me.”

Ever since his days on “Welcome Back Kotter” and through films such as “Saturday Night Fever,” “Grease,” “Urban Cowboy,” “Get Shorty” et al., and even through the career dips, Travolta has known what it’s like be adored by fans for the better part of five decades. In “The Fanatic” (opening Friday at AMC South Barrington and on demand), he’s on the other side of the velvet rope as Moose, a troubled movie fan whose obsession with his favorite action star, Hunter Dunbar (Devon Sawa), crosses over into “King of Comedy”/“Misery” territory.

Moose wears terrible clothes and sports an unfortunate mullet and is on the spectrum, as evidenced by his rocking and physical tics, some OCD behavior and a lack of empathy in certain situations.

“To have the audacity to do some of the things Moose does, you have to be of another norm,” said Travolta. “He literally doesn’t know any better.

“When the movie star rejects Moose and doesn’t give him an autograph, that’s the worst thing that could happen to Moose, because his love has been rejected. He’s been rejected his whole life, but he can’t conceive that his favorite movie star would reject him.”

Fred Durst — yep, that Fred Durst, from Limp Bizkit — wrote and directed “The Fanatic,” and had Travolta in mind for the lead when he was writing the script.

“I’ve known Fred for 10 or maybe even 15 years,” said Travolta. “I knew he could direct, because he had directed all these music videos. But I didn’t know he could do this level of writing.”

Travolta, who has a clean-shaven pate off-screen these days (“it makes life so much easier in the morning,” he said), sports a hockey-player-with-a-sense-of-humor level mullet in “The Fanatic,” which he said was at Durst’s suggestion.

“Fred said, ‘How do you feel about a mullet?’ Well, I’m normally not a fan of mullets, but Fred told me there are different kinds of mullets.

“So I went online and after going through about a hundred different mullets, I found this one guy with this great mullet, and I superimposed my face onto his picture and sent it to Fred, and he said, ‘Yep, that’s it.’ ”

Imagine the Mullet Guy out there who has no idea he was the inspiration for John Travolta.

Travolta has consciously avoided playing old-school leading men types, e.g., the hero in a cop movie franchise, throughout his career. For all his fame, he’s not one of those actors who is said to be “playing himself” or variations on a time-tested type in project after project.

“I love playing character parts,” he said. “Give me Robert Shapiro [in ‘The People v. O.J. Simpson’], give me Edna in ‘Hairspray.’ But don’t ask me to play me because I don’t even know who I am. I’ve [rarely] cashed in on my persona, except maybe in ‘Look Who’s Talking’ and ‘Phenomenon,’ where I was playing guys who were all personality. But coming from a theater family background, my goal was always to be honorable to creating. It’s more than just saying lines.”

In “The Fanatic,” with the exception of the Hunter Dunbar character, we see the Hollywood populated by people who never came close to realizing their dreams. They dress as icons of the past and hang out on the Hollywood Walk of Fame, but they’re nearly invisible.

“Quentin has a love affair with L.A., but this is a sadder L.A. than he depicts,” said Travolta.

“I think Quentin’s L.A. has hope. This movie, the characters might have hope, but it’s a dim light. …

“Think about the [scene in ‘Pulp Fiction’] at Jack Rabbit Slim’s, where I’m walking past Marilyn Monroe or James Dean, these tragic figures but it’s in a happy restaurant atmosphere.”

We talked about some of the other characters Travolta has made famous, and how it would be interesting to catch up with some of them all these years later.

“I always thought Bud from ‘Urban Cowboy’ would be fun to re-visit, and Debra [Winger’s] character as well,” said Travolta. “And ‘From Paris With Love,’ that was begging to have a sequel, that was as badass as it gets in terms of style.

“I’m just so happy that everybody’s got a different favorite film of mine. As a kid, if someone had asked me my fantasy, I might have said that one day I would have done so many different characters and been allowed to play so many different characters that everybody had a different favorite. Not every actor is allowed to do whatever they want. It is a beautiful permission to have, it is a gorgeous permission.”