Stop for a minute and think about the contrast between illusion and reality.

Where does one stop and the other begin?

That’s what Frankie Valli found himself considering the first time he watched a run-through of “Jersey Boys,” the mega-hit Broadway musical that depicts Valli’s rise to fame in the 1960s with the band that would become famous as the Four Seasons.

“How would the word ‘strange’ sound to you?” Valli said the other day. “It’s like a reflection of yourself. You look in the mirror and all of a sudden the reflection you see in the mirror is doing you. And you’re just standing there watching.”

To call Valli an iconic figure in pop music might be an understatement. He and the Four Seasons scored 40 Top 40 hits, including eight singles that went to No. 1. Most of the songs were written by the group’s co-founder Bob Gaudio. Today many of them - “Walk Like a Man,” “Sherry,” “Big Girls Don’t Cry” - remain instantly recognizable. What makes them so, aside from Gaudio’s expert craftsmanship, are Valli’s utterly unique falsetto vocals.

But Valli said he didn’t realize he was doing anything special.

“The magic that may seem to be there was something that was normal and natural,” he said from a tour stop in Denver. “I never studied singing with anybody. And I never thought that what I was doing was so incredibly unique. I thought anybody singing could do it. It took me awhile to understand that. I had this wonderful gift, and I loved using it.”

“Jersey Boys,” with which Valli and Gaudio were directly involved, is an international hit, and Valli said there are plans to adapt it as a film, which could begin shooting as early as January. In terms of the story, which depicts the group’s early struggles, the conflicts among bandmates, brushes with organized crime and eventual success as recording artists, Valli said the show is “95 percent accurate.”

As depicted in “Jersey Boys,” singers couldn’t work their way up in the music business without encountering the mob. Valli said Rusty wasn’t really modeled on anyone he had ever known, but he was a type he knew well, the kind of guy who was part of the social fabric.

“There isn’t a city in America where at certain points in time there wasn’t an organized crime situation going on,” he said. “Every city in America had something, whether it was Philadelphia or Kansas City or Los Angeles. I grew up in the middle of it. I grew up in a very Italian neighborhood that was mixed. But I knew a lot of those kinds of people. Those were the guys who owned the clubs we worked in. That’s just the way it was.”

Valli came up at a time when the music business was very different. In the 1960s its foundation was virtually a 19th-century industrial model: You made recordings, which were pressed as albums and singles at a factory and then trucked out to record stores. Top 40 radio programming included a wide variety of music - pop groups like the Four Seasons alongside R&B artists, soul singers and British rock bands - and making personal connections with DJs was crucial.

Now we’re in the age of digital downloads, automated radio and consumer-programmed digital “stations,” but Valli admitted there are things about the old music business he misses.

“I think technology does change things,” he said. “I don’t know if it’s better. I miss the record stores and the radio stations. I can remember a period of time just in New York City when there had to be eight or 10 radio stations playing pop music. That’s all gone.