Mike Anderson has a message for the Knicks and their fans.

You’re going to love Bobby Portis.

“He’ll be the first one in the gym and the last one [to leave]. Fans of the Knicks will really have a great appreciation for how hard he works,” the new St. John’s coach told The Post this week following a workout. “But not only that, what he brings to the table.”

Anderson would know. He coached Portis for two years at Arkansas, helping develop the 6-foot-11 forward and former SEC Player of the Year into a 2015 first-round draft pick, the Bulls taking him at No. 22.

Portis, a 24-year-old skilled power forward who shot 36.1 percent from 3-point range last year for the Wizards and Bulls, was part of an underwhelming offseason for the Knicks that saw megastars Kyrie Irving and Kevin Durant sign with the rival Nets. Portis wound up coming to the Knicks on a two-year, $31 million contract that guarantees just the first year. He’ll be joined by other young players on short contracts such as power forward Julius Randle, point guard Elfrid Payton and shooting guard Reggie Bullock.

“Where he is [in his career], I think he’s a great fit,” Anderson said. “He’s the ultimate team player, but he’s a pretty good talent as well.”

His work ethic and intensity remain the qualities Anderson appreciates the most in Portis, describing them as “second to none.” His temper did get the better of him two years ago when he punched out teammate Nikola Mirotic after a practice during the 2017-18 season. When Dwyane Wade questioned some of the young Bulls’ work ethic, Portis stood up to him, defending how hard he works.

“He wants to be a great player,” Anderson said. “He’s the ultimate competitor. People don’t realize he has a drive and passion that’s unbelievable.”

It’s what made him into a McDonald’s All-American and led him to garnering SEC Player of the Year awards in a conference that included Karl-Anthony Towns and Devin Booker. He’s averaged double figures each of the last two seasons and is coming off a career-best 8.1 rebounds per game.

Anderson is excited to see his former player up close. While the Nets may be adding fans after their big offseason haul, the Knicks have a new one in Anderson thanks to the addition of Portis.

“I think it’s very cool. It’s pretty neat,” he said. “When I got here, my nephew DeMarre [Carroll] was with the Nets. I got a chance to see him play. Now all of a sudden Bobby has an opportunity to come here and continue his tremendous career in the NBA.

“I’m excited, I’m excited for him. It’s kind of cool I get a chance to continue to see him play.”