We know all about Mike Tyson. Or so we think. That’s how most Americans score it on their celebrity fight cards.

Not even close. The former heavyweight champ – as savage in his prime as any heavyweight champion most of us have ever seen – is in season. The first radical revision you’ll have to make about the Mike Tyson you’ve, no doubt, been carrying inside your head begins at 8 p.m. Saturday with HBO’s Showing of Spike Lee’s “Mike Tyson: Undisputed Truth,” a record of his 2012 one-man show on Broadway.

And then, at virtually the same time, will come his autobiography published by HarperSport “Mike Tyson: My Undisputed Truth.” It seems to me that win, lose or draw, that’s a necessary American book, one we’ve long needed for the record. (Our review of the book will come closer to its Nov. 21 publication date.)

But that might seem to be a celebrity operating in a standard way according to the new media rules, i.e. live your life, ride high, be brought low, do your penance, write your story, do as much TV as you can to let people know you’ve done it and then sell the hell out of books.

What you have to see in Lee’s HBO record of Tyson’s wholly unexpected one-man show is precisely how verbal he is. That he is bipolar has been reported for many years, but unless you know him or you’ve been a journalist covering him up close and personal, you’ve never seen Tyson explode with a manic street jiving barrage of words, jokes, imitations of people both loved (his legendary mentor Cus D’Amato) and loathed (Don King).

That is the crazy news in what Lee and HBO are now making available for everyone all over the country to see. That’s the canny thing to do with Tyson on his “Buy My Products” redemption tour: You make him the neighborhood’s greatest celebrity who has somehow commandeered the local grammar school auditorium for 90 minutes to jump, jive and wail (as Louis Prima might have put it) his life story in your face.

You have to consider that, up to now, he’s generally known in America for his ring performances (including ear-biting) and that bizarre, high-lisping voice of his that makes him sound like an MGM cartoon character from the ’50s. Until Saturday’s broadcast of his one-man show on Broadway, we’ve mostly seen Tyson only piecemeal, and in small pieces at that. (James Toback’s film documentary was an exception.)

The game Tyson has played with the world up to now has been a kind of Muhammad Ali rope-a-dope. He lets himself get pummeled in the media. Then he lashes out in fury (“He’s crazy,” sings the press in chorus when he does) and goes back to standing there to get pummeled some more.

He’s always mediated by someone else – most famously by his apparently gold-digging ex-wife Robin Givens in that joint interview with Barbara Walters in which she virtually accused him of brutality as he sat there. Usually, there’s someone else to filter him first, as if he were either too stupid or too unpredictable to be allowed to present himself to the world for long periods without gloves on.

No more. You can multiply that times 10.

Obviously, of course, he’s mediated by others here too – Spike Lee, of course, who’s presenting Tyson to us, and Tyson’s wife, Kiki, who co-wrote the script for his one-man show with playwright Randy Johnson.

Tyson, it turns out when he bobs, weaves and bounces around the stage spraying his memoir into the air, isn’t just the richest and best-known guy in the neighborhood (and the one with the most violent, roller-coaster fortunes), he’s also the most interesting.

God bless Spike Lee. That’s why we’re finally seeing uncut and unmediated for 90 minutes – street corner Mike, telling his tale in his cartoon voice to all the black and white liberal fans he knows he’s got in the audience, laying himself over their indulgences, exploiting their prejudices and sharing really good jokes with them that he knows are going to entertain them almost as much as Ali once did.

There’s an ancient tradition, of course, of fighters and sports heroes taking to the stage to do monologues and “performances” of one sort or another for an adoring and paying public. It goes back past Babe Ruth to John L. Sullivan.

The outline of Tyson’s “Up From the Streets” tale is well-known legendry to those even tangentially interested in boxing – as much as any American boxer who ever lived, including Ali.

What he tells us in his HBO performance is that “by the time I was 12 years old, I was arrested 38 times.” It was kind of like “Cheers” when they brought him to the police station, says Mike – you know “everybody knows your name.”

“I didn’t come from a home where memories were cherished in proudly displayed photo albums,” he says. “I grew up in the gutter, a place where dreams were broken and memories best forgotten.”

All well and good and eloquent enough, but Mike remembers. And his audience loves it.

He was, for instance, once “a fat kid with glasses.” And then at 14 he discovered his calling.

He kept pigeons. “My first fight started over one of my pigeons. Gary the Bully took my pigeon that I had stolen and snapped his neck.” Mike mimes it for us, in case the cruelty of it passed us by. “My rage let loose on him and I beat him up pretty bad. It was love at first fight.”

So much for being the fat kid with glasses with the funny voice.

When D’Amato entered his life, he taught him how to read and write – and fight. “Cus had my back and my talent was” undeniable, he said, inserting an expletive. But “he was an old stubborn man with a hacking cough” and couldn’t last forever.

Then the Tyson circus starts, about all of which Tyson is nothing but entertaining – nasty and dismissive as can be about ex-wife Givens (when she was trying to relaunch her career, says Tyson, she was going out with Brad Pitt, who didn’t seem proud of it) and absolutely hilarious about his after-hours scuffle with Mitch Green, a heavyweight he’d won a decision against but couldn’t put down.

Their unsanctioned street bout took place outside a Harlem clothing store called Dapper Dan’s. As Mike explains, “Mitch is a Neanderthal. I’m half a Neanderthal.”

His shocking demolition in the ring by Buster Douglas he drolly calls “a bad day at the office.”

As for his Indiana conviction for raping Desiree Washington, he still denies it (“I did not rape Desiree Washington and that’s all I’m going to say about this”) and lays his conviction at the feet of the “tax attorney” whose defense services had been secured by that renowned gentleman of ever-dubious patronage, Don King.

Jail? Well, he tells us it was good for him. “There is no better time to reflect than to be in a place where you have all the time to do so. Never did I think I would go into prison with all of my emotional issues and come out finding some peace.”

In case he needed company, people like Lee, Whitney Houston, Tupac Shakur and Maya Angelou dropped by to say hello (so also, swears Tyson, did Florence Henderson of “The Brady Bunch” but she couldn’t get past the guards.)

You won’t hear his disquisition on chomping on an opponent’s ear in the ring but you will hear how the nice folks at Wrestlemania once tried to lure him with their siren song: “The wrestling is fake, but the checks are real.”

“Never run, never will,” he says, is the ethic he learned growing up in the Brownsville section of Brooklyn.

Who’d have imagined he’d also learned how to be this entertaining?