If Kevin Durant wants to come to the Knicks, he had better bring along another star or he’ll wind up like Patrick Ewing — ringless.

So says Brooklyn-born Bernard King, the former Knicks legend who played a role this past season as rookie Kevin Knox’s unofficial mentor.

King, who signed as a Knicks free agent after starting his Hall of Fame career with the Nets, said he still believes New York is a hot spot for NBA players, and the trio of president Steve Mills, general manager Scott Perry and coach David Fizdale will prove inviting to free agents.

“My thing was always to play for the Knicks, but I was from Brooklyn,’’ King told The Post in a phone conversation from his Atlanta home. “I believe … they have a group of men who clearly know and understand the game, and they’re good managers. Any player should want to play in a city like New York. The fans are great, and they now have one of the best organizations after making the changes. Why wouldn’t Kevin Durant want to play in New York?”

Durant could follow in King’s footsteps by leaving the Warriors for the Knicks. King, who did so in 1982, wouldn’t advise the move, however, if the 30-year-old Durant would be going solo with a young Knicks roster.

“I think that given the fact they have space for two max contracts, he needs someone else to come along,’’ King said. “That’s what you see around the league. Superstars playing together. Who that other player that would be — Kyrie Irving, Kawhi Leonard — I don’t know. But if [Durant] decides to play in New York, he needs another superstar beside him. That’s what happened with Patrick. He had very good players in Charles Oakley and John Starks, but he didn’t have another superstar to play with him.”

King grew up in Fort Greene, a five-minute walk from where Barclays Center now stands. He said he believes the Nets could give the Knicks a free-agent run for their money after a playoff year, given their New York location.

“They’ll be attractive to a number of free agents,’’ King said of the Nets. “They have a wonderful arena and a good coach [Kenny Atkinson] and very talented players.’’

But King said the Knicks are “a fabled franchise,” giving them an edge. And, if you add Durant and Irving to the baby Knicks, Kings said he feels they would become “a contender.’’

“It’s about superstars in the playoffs — when you go into a close game you need players to control the game,’’ King said. “New York is a great market for a superstar. Hopefully they’ll sign Kevin and another superstar comes along with him.”

Fizdale has said he considered King his favorite player growing up in Los Angeles and enlisted the former Knick to work with Knox during his roller-coaster rookie season.

King’s tutelage paid off in Knox’s uptick the final month. King tutored Knox in Atlanta when the Knicks visited, convened with him in Boston, where they shared dinner, then he attended two practices in Tarrytown.

King, who recently published his memoir “Game Face,” is a student of the game and considers scoring a science.

King, who averaged 22.5 points in a 14-year career despite ACL surgeries, advised Knox on several matters. King sensed Knox needed to be in better shape, needed better technique on finishing at the rim and needed to understand all the exact spots on the floor he could operate.

“When he was going downhill, he was fading,’’ King said, “instead of going directly to the basket. When he gets close to the basket, he would fade to the right instead of going straight up to the hoop. It didn’t give him a chance to get fouled or to score.

“I spoke to him about how he runs the floor. Some people think it’s elementary. It’s not. I’m not criticizing Knox but you can always improve how you run the floor. It was one of the things I did very well.”

Another alarming trend was Knox coming out of the gate on fire then disappearing in the final three periods.

“A lot of rookies hit the rookie wall,’’ King said in his first public remarks about Knox. “One of the things I spoke to him about is try to make the treadmill part of your workouts and that will help the conditioning level. Treadmill was a huge part of my workout routine. There’s so many talented players in the league, you have to have an edge. Conditioning is an edge. I really never got tired because I worked on the treadmill.’’

Knox was “receptive’’ to his teachings, King said. Three weeks ago, Fizdale worked with Knox for a week in the Tarrytown gym to pound home King’s principles.

“Knox has developed,” King said. “He just needs to bring his conditioning up.’’