LeBron James is ready for his close-up -- in Trainwreck

Amy Schumer and Bill Hader are billed as the stars of Trainwreck because… well, because they are the stars of Trainwreck. And no doubt about it: They are nothing short of amazing in director Judd Apatow’s wild and crazy rom-com (which Schumer scripted), striking a dead-solid-perfect balance of uproarious R-rated hilarity and stealthily affecting sincerity while playing, respectively, a commitment-averse magazine writer who views love roughly the same way Superman views kryptonite, and a renowned sports-medicine surgeon with an all-star lineup of satisfied customers.

But while Trainwreck (which opens July 17 at theaters and drive-ins everywhere) is bound to earn copious kudos for the above-the-title leads – and for Apatow, who’ll add the film to a sterling resume that already includes The 40 Year Old Virgin and Knocked Up – don’t be surprised if critics and audiences also heap praise on the star-making performance by a supporting player who’s already a superstar: LeBron James.

Yes, that LeBron James, the celebrated Cleveland Cavaliers power forward who’ll be leading his team this week and next against the formidable Golden State Warriors in the NBA Finals.

But no matter how things shake out on the hardwood courts this week, you can take this to the bank: The superstar known as King James already is establishing himself as an MVP in a whole different game.

At least, that’s the early scouting report by critics who viewed Trainwreck last March at the SXSW Film Festival in Austin. Variety film critic Scott Foundas said the film’s “biggest surprise is indeed James, who plays himself — or, rather, a self-aggrandizing, penny-pinching version of himself — to deadpan perfection.” Ryan Bort of Esquire.com agreed, noting: “[James’] role is larger than anyone could have imagined, and his performance is certainly the best and most substantial foray into acting we've seen from a sports superstar of his magnitude.”

In the world according to Trainwreck, LeBron James is a sage and sensitive soul whose deep and abiding friendship with Dr. Aaron Connors (Hader) is strained only when he fears his buddy might make him miss an episode of his favorite TV series, Downton Abby. (“Listen, I’m watching it tonight,” he tells Aaron, “because I’m not going to practice when all the guys are talking about it – and I’m left out!”)  He’s initially happy to hear that Aaron has, well, scored. (“My boy got intimate! Sexual intercourse! Whoa-ho!”) But he frets that someone as anti-monogamy as Amy Townsend (Schumer) might break Aaron’s heart. And when Aaron does indeed find that love is a hurtin’ thing, King James is quick to stage an intervention with a back-up team that includes Marv Albert.

Yes, that Marv Albert.

When I caught up with Judd Apatow in Austin the morning after Trainwreck premiered at SXSW, we spoke about many things – the brassy wit of Schumer’s screenplay, the seriocomic grace of Hader’s career-best (so far) performance, his own history of supporting fresh talents like Schumer and Lena Dunham, etc. But I made sure I saved enough time during the interview to ask: So, Judd, tell me -- what was it like to work with LeBron James?

“When Amy wrote his name in the script – well, that was the dream,” Apatow said. “In a situation like this, you never think you’re going to really get LeBron James – you think you’re going to get somebody who retired from the NBA in 1968."

But thanks in large part to Bill Hader, an alumnus of Saturday Night Live, the dream became a reality.

“Bill had meet LeBron when he hosted Saturday Night Live, and told us that he was a great guy and super funny,” Apatow said. “So Bill and I took him out to lunch, and we talked a little about his part, which in a lot of ways is the Bruno Kirby part in When Harry Met Sally… We thought that it would be really funny if that person just happened to be the greatest basketball player in the world. And LeBron really laughed.”

Which isn’t to say King James took his movie debut lightly. Indeed, “LeBron showed up as a very well-prepared actor,” Apatow said. “He was very loose, he was willing to experiment and improvise just like everybody else, and he revealed himself to be riotously funny -- which we are all jealous of.”

But wait, there’s more: LeBron James arrived just in time to make his “character” a very eloquent and passionate spokesman for Cleveland.

“His shooting days started a week after he announced that he was going back to the Cleveland Cavaliers,” Apatow said. “So we quickly added that to the script.

“But, you know, he’s always telling people he’s the mayor of Cleveland.”

Trainwreck also features a very funny cameo performance by another NBA notable, Amar’e Stoudemire, as another of Aaron's patients. Ironically, he filmed his part before he moved from the New York Knicks to the Dallas Mavericks – at a time when he doubtless had no qualms about saying “Dallas sucks!” on screen.

“We watched all these different athletes on Letterman,” Apatow said, “because we figured if they're funny with Letterman, we know we can make them funny in the movie. Amar'e was so charming and witty -- and he also turned out to be a great guy to work with. And he carried off some difficult moments, like where he’s doing that whole bit when he’s supposed to have just come out of surgery.”

So what is Judd Apatow’s secret? How does he get such effective performances -- such funny performances – out of superstars who are, essentially, non-actors?

“My favorite thing with any actor or actress,” Apatow said, “is to let them know that they have enough time to figure it out. I think when people are rushed, they can't act. And when they feel under pressure to make it perfect right away, that's when people panic. I always tell them, ‘Look, you have plenty of time, we are going to do a lot of takes." And usually just that information gets them almost all the way there.

“The nightmare that a lot of people have is that they’re only gonna get one take, some crappy shot, and someone's gonna say, 'OK, check the gate! We're done!' But I always just say, 'We're not going to move on until you're happy.'"