When Jim Parsons first strolled the Hollywood Walk of Fame as a teenage tourist from Houston, he didn’t have the sort of epiphany Sheldon Cooper lives for.

“I already enjoyed acting,” Parsons says on a break from shooting “The Big Bang Theory.” But “there was not some sort of sense of ‘maybe one day.’ It did not even enter my mind.”

Parsons is delighted, in his own quiet way, to become a name on Hollywood Boulevard. “I like how all-encompassing it is,” Parsons says. “It could be radio announcers you have never seen before or very, very visible and famous actors.”

The busy thesp is preparing for his third run on Broadway in the spring, but his star is in the TV category for playing the socially maladroit, brilliant physicist Cooper on the mega-hit CBS comedy. During its eight seasons, Parsons has continued to expand the role, though he knew he nailed it in auditions.

“It sounds really conceited,” Parsons admits. “It was in the thick of the pilot season and this was the 40th thing I had read. And if you are going to read that many things over a few weeks your eye gets really keen of what is going to come out of your mouth believably.”

“Big Bang” made Parsons a star and led to his Broadway debut in the 2011 revival of “The Normal Heart,” Larry Kramer’s gut-wrenching play about the early days of the AIDS epidemic. When the drama became an HBO film three years later, Parsons was the only actor to reprise his role from that production.

Joe Mantello, who played different parts in both versions, had not heard of Parsons before they started rehearsals. “I remember when we moved into the theater, and I was walking in midtown and saw his face on a T-shirt,” Mantello says. “And I said to him, ‘Do you have a catchphrase on your TV show? Is it bazooka?’ He said, ‘Bazinga!’ ”

Another co-star, who has come to adore him but didn’t know Parsons before they worked together, is Mayim Bialik, who plays Sheldon’s love interest Amy Farrah Fowler.

Playing a theoretical physicist on TV’s biggest comedy, “The Big Bang Theory,” has transformed Jim Parsons from working actor to superstar.

“I was specifically called in to do a ‘female Jim Parsons,’ ” Bialik says. “My manager was super annoyed she had to explain who Jim Parsons was because apparently everyone else knew. I watched 15-20 seconds. As a neuroscience grad student I met people like that all the time.”

Unprompted, Bialik and Mantello both mention Parsons’ humility, a quiet decency that was almost palpable when he starred in Broadway’s “Harvey” in 2012.

“I don’t know that there is another character out there with a more generous open spirit,” Parsons says of the role immortalized by James Stewart in the 1950 film. “There is something Jesus about him, something Dostoyevsky’s ‘The Idiot’ about him. He is a magical presence in a way. And any character you get to play is the chance to see the world through their eyes for a while.”

“He reminds me of Jimmy Stewart,” Bialik says of Parsons, whom she calls beloved. “He has a real physical presence. The way he holds himself reminds me of Clark Gable. Certain things about him are so heroic.”

Parsons’ next Broadway role will be less likely to draw physical comparisons. He’s the Almighty in the one-man play “An Act of God,” directed by Mantello. “I could count on one hand the actors I would feel comfortable with going into this,” Mantello says. “It is a massive undertaking — just the sheer volume of the number of lines he has to learn.”

“God has some stuff he would like to say and he has decided a venue on Broadway is the way he would like to do it,” Parsons says, pitching the play’s set-up. “And since his essence defies all comprehension by humans, one of his choices is to take over a body and speak through them and the conceit is he has picked me.

“It could easily be Angela Lansbury,” he says. “It could easily be Denzel Washington. I find this process delightful.”

What would truly delight Parsons would be to do more movies (he voices the lead character in DreamWorks Animation’s “Home,” opening this month) but TV’s shooting schedule keeps him busy. “(It’s) the golden handcuffs of television, and I wouldn’t trade it for the world,” Parsons says. “One of these days this show won’t be happening anymore and I will have more time than I want.”

Even if he had unlimited leisure time, Parsons doesn’t envision himself hanging out on Hollywood Boulevard, removing litter from his star.

“It is a funny place to honor anyone,” Parsons says. “ ‘We will put your name right on the ground.’ And if there is gum there? Come on, it is the ground!”