Less than a year after Magic Johnson pitched LeBron James on a “Showtime” revival, the Los Angeles Lakers president abruptly resigned without giving his superstar forward advance notice.

In his first extended public comments since Johnson’s stunning exit April 9, James said that Johnson’s curious timing and lack of forewarning rubbed him the wrong way.

“It was just weird for [Johnson] to just be like . . . ‘Nah, I’m out of here,’ ” James said on an episode of “The Shop,” his HBO show, that aired Saturday night. “And not even have [a heads-up] like: ‘Hey, Bron . . . kiss my a--. I’m out of here.’ I would have been okay with that. Like: ‘Hey, Bron, it’s Magic. Kiss my a--; I’m gone.’ It wasn’t even that.”

Johnson held an impromptu news conference at Staples Center before the Lakers’ final game of the season, telling reporters he was resigning immediately and admitting he hadn’t informed team owner Jeanie Buss of his decision. The 59-year-old said that he would “be giving up a lot of me” if he remained team president, and he added that he felt “handcuffed” by NBA tampering rules, which prohibited him from talking about players on rival teams.

James, who was shut down for April because Los Angeles was eliminated from the playoffs, described hearing the news from Randy Mims, his longtime friend and business partner. Mims told James that “Magic just stepped down” while the four-time MVP was going through pregame stretching exercises.

“What do you mean [stepped down]?” James recalled telling Mims. “Like, from out of his car? I’m like: ‘Man, get the f--- out of my face. You’re bulls---ting me.’ ”

James relayed the news to teammate Lonzo Ball, and the news spread through the locker room from there.

“We were like, ‘Damn, right now?’ It was literally 70 minutes on the clock before [tip-off],” James said. “[The team] is getting ready for a game. And you decide to do that right here, right now? I feel like there’s a time and place for things, and I believe that you knew you were going to make that decision. So why would you do it here? And why would you do it now?”

James’s description of the events of April 9 confirms media reports that Johnson hadn’t consulted with the superstar or his agent, Rich Paul, before his announcement. In the immediate aftermath of Johnson’s decision, James remained mum, declining to speak with reporters after the team’s finale and skipping exit interviews so he could attend the final game of Miami Heat guard Dwyane Wade’s career April 10 in Brooklyn.

Johnson and Lakers General Manager Rob Pelinka recruited James, signing him to a four-year, $154 million max contract shortly after free agency opened last summer. As a five-time champion, a Hall of Famer and a billionaire business mogul, Johnson was viewed as a mentor for James on and off the court.

James recounted a conversation in which Johnson pitched him on a long-term vision of rekindling “Showtime,” which included acknowledgements from the Lakers president that the 2018-19 season was “going to be tough” because the Lakers “were a young crew.”

“I came here to be a part of the Lakers organization [after] having a conversation with Magic,” James continued. “[He was] really kind of breaking it down and saying how we were going to make this ‘Showtime’ again. I wanted to be a part of that process.”

James, 34, suffered a significant groin strain on Christmas and appeared in a career-low 55 games. As a result, the Lakers missed the playoffs for the sixth straight year, and James failed to appear in the postseason for the first time since 2005. The messy campaign, which included a failed trade pursuit of New Orleans Pelicans star Anthony Davis, cost coach Luke Walton his job last month.

James said that he entered his Lakers tenure with his eyes wide open but noted that the lost season, in which “injuries kind of f---ed us,” was costly to him personally.

“We all knew that it was going to be kind of tough,” James said. “But I was okay with the process. At year 16, you aren’t really supposed to be worried about no d--- process. Especially for me, because I’m in championship mode all the time.”

Set in a barbershop, “The Shop” is a 30-minute conversational show. James and Carter are executive producers of the show, which is a collaboration between HBO and James’s media company, Uninterrupted.