Bernard King sat on the Garden’s celebrity row Tuesday, when the Knicks hosted Charlotte, and said he’s never seen anything like it.

One of many, King is in awe of Kristaps Porzingis, who is off to the best start in Knicks history after a dozen games, averaging 30.4 points.

An offensive technician, King, one of the best pure scorers in Knicks history, sees elements of Porzingis’ greatness beyond the obvious shotmaking, including court vision and passing ability that are overlooked and untapped.

“I’m sitting there watching the game against Charlotte,’’ King told The Post before his Monday book-signing event at the Garden and NBA Store. “He’s hitting shots 3 feet behind the 3-point line. It’s unheard of. I’ve never seen anything like it. And he’s capable of hitting mid-range and posting up.’’

And Porzingis’ gifts go beyond that for King, the 1980s legend who just released his memoir “Game Face’’ and is amid a month-long book-signing tour.

“There’s been a number of players who’ve played with significant height advantages — at 7-3, 7-5, 7-7,’’ King said. “I’ve always said height doesn’t play basketball but talent does. Porzingis is an exceptionally talented young man but beyond, he has a tremendous basketball IQ.

“He understands basketball — the game within the game. He’s able to take advantage of his skill-set — height being one of them. Most big men that height don’t have his range, but his other key things are peripheral vision. He sees the floor very well. He sees cutters and guys spotting up. He has tremendous passing skill. Also on defense, he’s a great shotblocker because he understands placement on the court and where he is at all times.”

The defenses will get even rougher and tougher against Porzingis, King predicts. But King doesn’t want him to get bulkier, despite his thin frame.

“Teams will get more physical with him,’’ said the Hall of Famer from Fort Greene, Brooklyn. “With his height, I don’t think he needs to bulk up and fight that physical play by the opposition. He still needs to be that finesse player and not a power player. You don’t have to fight the guy for the deep low-post position. All you have to do is take what the defense is giving you, and he has the ability to just turn around and shoot. He’s very efficient. I love watching him play because he knows the game.’’

Does he have the tools to one day become regarded as the best ever Knick? Championships — not scoring averages and All-Star berths — will determine that, according to King, who averaged 32.6 points as a Knick in 1984-85. Porzingis broke King’s record for most points after 10 games (300-to-296) last week.

“It’s too early to say,’’ King said. “I believe we’ll have to wait until you face tougher opponents — the Spurs, Golden State, Houston and the Cavs. Then you start to find out how well he’ll play at that level. I don’t think there’ll be any drop-off. You’re talking about the best, overtaking Walt Frazier, Willis Reed, Patrick Ewing. He’s not there yet, but he’s on his way. Let’s enjoy the ride.”

King was Carmelo Anthony’s idol growing up and has a soft spot for the ex-Knick now in Oklahoma City. Anthony’s seven-year legacy that saw just one playoff-series win and four straight years out of the postseason was not on him, according to King.

“He’s one of the all-time greats to ever play the game,’’ King said of Anthony. “But Patrick needed another superstar next to him. Carmelo never had another superstar next to him. I never had another superstar next to me. In the NBA, the last 30 years, you’re not going to win a championship unless you have at least two superstars. He did the best he could with what he had to work with.”

And Porzingis, says King, will need another star not currently on the roster for the Knicks eventually to end the title drought that dates to 1973.

“We’ve arrived with Porzingis,’’ King said. “He’s going to need — and they’re playing well as a team — he’s going to need another superstar in New York to compete against great teams.”

King, who will attend Monday’s Cavaliers showdown, said his lone regret was never playing alongside Ewing. They’ve both told each other a Knicks title would have been captured if they had. As far as his autobiography, King said he turned down many offers in the past to compose one but agreed one year ago to “go forward with some secrets.”

“Game Face’’ details his early-career drinking problems and ugly shouting matches with former Knicks coach Hubie Brown.

“People know Bernard, but they don’t know Bernard King,’’ he said. “[The drinking] almost resulted in loss of my career.”