Confession time: As a kid who lived and breathed the television show “Hawaii Five-0,” I got totally stoked whenever I heard its hard-charging theme music. Oh, those pounding drums, those blaring horns, that rolling wave …

Occasionally, I’d even dress up in my dad’s suit, turn up the volume on the stereo and run around the house like a mad little dork pretending to be detective Steve McGarrett in a gunfight with vicious island thugs.

Let me just say: Coolest TV theme song ever.

So you can imagine how pleased I was to hear that the iconic tune is being incorporated into CBS’ rollicking reboot of the series, scheduled to premiere Sept. 20. After all, you just can’t get “Five-0” right without getting the music right.

Ah, but they almost screwed it up. Executive producers Alex Kurtzman and Peter Lenkov admitted during the TV press tour that, at one point, they considered having a “popular rock star” come in to redo the theme with an electric guitar. Horror of horrors.

Eventually, though, they came to their senses and did it with a 35-piece orchestra conducted by the show’s composer, Brian Tyler. They even brought back some of the original musicians to participate in the re-recording.

Says Kurtzman, “We decided that you just don’t mess with perfection.”

What else is new?

As for other aspects of the show, the producers felt free to tinker. The pilot episode, made available to critics, is a turbocharged hour full of action, escapist fun and the kind of special effects not available back in the day. There’s also a sense of humor that the stone-cold serious original lacked.

The biggest changes revolve around McGarrett. The Big Kahuna of crime fighters will no longer sport Jack Lord’s lacquered black pompadour or deploy the kind of icy gaze that could freeze molten lava. As played by Alex O’Loughlin (“Moonlight”), the modern McGarrett will have a different kind of vibe.

“I love Jack Lord’s McGarrett. I love Jack Lord’s hair. I think he started blue steel (with) the look that he does.” O’Loughlin told reporters. “But I can’t get away with that today in 2010.”

O’Loughlin’s McGarrett is still a stoic ex-military guy, but he has a bit more hang-looseness to him. In the new version, we’ll also delve deeper into his tragedy-marred back story — something the original mostly avoided.

“This guy is a really interesting case study for me as an actor and as a sort of researcher of human movement,” O’Loughlin says.

One more change: Whereas the original had McGarrett’s lead assistant, Danny Williams (James MacArthur) serving as little more than a yes-man, the new “Five-0” presents a Danno played by Scott Caan (son of James Caan) who often butts heads with the boss and engages him in spirited banter.

“He’s McGarrett’s right-hand man,” Lenkov says. “But he’s really an equal in terms of his experience and what he brings to the table.”

Rounding out the cast are Daniel Dae Kim (“Lost”) and Grace Park. The latter adds a touch of femininity that was virtually non-existent in the testosterone-laden original.

But one thing hasn’t changed: Like its predecessor, the new “Five-0” is brimming with gorgeous island scenery, which looks all the more vivid and vibrant in sparkling high-definition cinematography.

“Hawaii is definitely an important character on the show,” says Kurtzman. “Hawaii is the fifth Beatle.”

Sounds good to us. Book it, Danno.

“Hawaii Five-0”

When: Premieres Sept. 20

Where: CBS