Five kilos.

That’s how much weight 7-foot-3 Kristaps Porzingis told his former big-man coach in Spain he’s gained since starting the Knicks’ weight-training program five weeks ago.

Five kilos equals about 11 pounds. Audie Norris, who coached Porzingis last season with Cajasol Sevilla, spoke to the 20-year-old Latvian he calls “Zinger’’ this weekend.

“The kid’s got a good appetite,’’ Norris told The Post in a phone interview. “He’s aware he has to put on weight. That’s going to be a big part of his pro career — to gain muscle. It will help him in the long run.’’

The skinny Porzingis was drafted with a listed weight of 233 pounds.

“He’s ecstatic, like a kid at Christmas,’’ Norris added of Porzingis’ summer training at the Knicks’ facility in Tarrytown. “He said, ‘It’s amazing how we got everything here. I don’t see how NBA players can become lazy and not work out with everything available to them.’ ’’

The 6-foot-9 Norris, who played three seasons for the Trail Blazers in the early 1980s, was hired by Sevilla essentially to work with Porzingis on his inside game. He also aided another Knicks draft pick — the less-heralded center Guillermo Hernangomez, whom team president Phil Jackson plucked with the 35th pick after buying it from the Sixers.

Norris, 54, calls Porzingis and Hernangomez his “young black lions.’’ Hernangomez will spend this season in Spain while all eyes in New York are on Porzingis, the controversial fourth-overall pick who was booed mercilessly on draft night.

“I think he’s going to do very well his rookie season, because he has more confidence than fans really know,’’ Norris said. “The Knicks did a good job of looking at Kris in all aspects. I don’t think Phil would’ve wasted a high draft pick on somebody who wouldn’t contribute his first year.

“His work ethic is really, really high. Not trying to sound like an agent. I coached him and know his potential. He’s doing everything in his power to prove the fans who booed wrong.’’

Porzingis also has to prove himself to Jackson. The Zen Master said — according to Charley Rosen’s “The Phil Files” published by ESPN — Porzingis could prove too tall for his own good, not having a strong enough foundation, comparing him to 1990s draft-bust Shawn Bradley.

Norris’ mission was to make Porzingis comfortable inside.

“The first thing everyone knew about him is he’s a perimeter player who shot the ball well, but my focus was to improve his interior game, which he didn’t have,’’ Norris said. “He was all face-up jumper, 3-point shooter. We focused on a post-up game, jump hook, back to the basket.’’

And a bank shot.

“We had to develop with Kris was his turnaround jump shot off the glass,’’ Norris said. “He never shot a bank shot before. We worked on it and he got good developing it.’’

Porzingis scored on a banker from mid-range for his first points in July’s Las Vegas summer league.

“He called me to thank me for teaching him the bank shot,’’ Norris said. “I told him it’s a shot you’ll have the rest of his career. That was cool. Very proud.’’

Norris also had Porzingis play one-on-one in practice with guard Ben Woodside, who played at South Dakota State. It enabled Porzingis to work on staying low with his dribble, protecting the ball against smaller players. And it helped his lateral defense.

In 75 career games with Seville across three seasons, Porzingis averaged 8.1 points. He held up well in Vegas, averaging 10.5 ppg, as the starting center instead of what’s expected to be his natural position — power forward.

And unlike the Knicks’ most recent European player, the boorish Andrea Bargnani, Porzingis’ personality was refreshing. He’s amiable and his English is sharp. His presence in the locker room should be a bonus.

“Kristaps is definitely an extrovert,’’ Norris said. “He loved talking. Sometimes you can’t shut him up. Not one of the quiet guys. Kris wants information and he looks and asks for it. He wants to be better. He asks his teammates, coaches what can he do to get better. Not the silent type and very approachable.’’

Norris said he has a “strong foundation that’s stable’’ with both his brothers having played professionally in Europe. The Spanish season didn’t go smoothly as they finished .500 and coach Scott Roth was fired. But Porzingis showed leadership at age 19.

“A lot of young kids had to carry us,’’ Norris said. “He encouraged teammates to work after practice with him. He didn’t like losing. He did everything to keep his teammate engaged.’’

In Las Vegas, Porzingis impressed as a shot-blocker who didn’t back down from physical play and scored as much inside as outside. But he didn’t rebound — something Norris says is not “emphasized” in Europe.

“He’s going to improve his rebounding, shot blocking and defense because he’s going to get bigger and stronger, no doubt,’’ Norris said.