Warning: spoilers aheadLeBron James is certainly not the first or last professional sports star to be cast in a movie. But he's one of the few who can actually act.In 'Trainwreck,' the newest Judd Apatow comedy starring Amy Schumer (who also wrote the screenplay), James plays a version of himself who is good friends with a sports doctor named Aaron (Bill Hader) who falls in love with Schumer's character, Amy.It feels like a stretch that James would ever be buddy-buddy with a sports doctor in real life, but for a comedy it's incredibly effective, and that's thanks tothe surprising acting chops of the four-time NBA MVP.Jamesknows how to deliver a joke and looks calm in front of the camera, which has always been what kills the appearances of sports stars in the past (think Brett Favre in 'There's Something About Mary' or all the NBA stars outside of Michael Jordan in 'Space Jam").And Apatow/Schumer gave James a great character trait 'trying desperately to be relatable when you're a huge superstar.The first time we see James, he shows up to Aaron's office to find the sunglasses he left behind. When Aaron says, 'You drove back 40 minutes to get your glasses'' James answers back, 'I'm not giving Sunglass Hut another $30!'The fiscallyconservative attitude shines through later when James and Aaron have lunch and multimillionaire James is adamant that they split the check. When Aaron finally gives in, James realizes he left his wallet in the car.James holds his own opposite Hader, never looking overwhelmed and never trying to perform with an overplay of emotion.The funny thing is how James was even considered for the role.Schumer had James' name originally in the script, but not because she's a huge basketball fan. In fact, Schumer, like her "Trainwreck" character, knows nothing about sports.'He's the only basketball player I've ever heard of,' Schumer told Entertainment Weekly for their July 3 issue. But she was in luck.James has shown in the past that he can be a performer. He has cohosted the ESPY Awards and hosted "Saturday Night Live," but a movie is a different animal, especially when it's not just a cameo and the athlete is a crucial part of the story line.James especially shines in "Trainwreck"when he is playing basketball one-on-one with Aaron and they are talking about Amy (while James blocks every shot Aaron puts up). At one point ' again, poorly trying to relate to his buddy ' James goes on a long tangent about the consequences of having sex without protection. Not with a condom, but a lawyer. He explains the horrible aftermath of having sex with a gold digger (a common peril for someone of his fame) and in mid-sentence starts spouting lines from the Kanye West 'Gold Digger' song.James definitely has a second career he can embrace once he hangs up the sneakers.'Trainwreck' opens in theaters on Friday.Here's a bit more of James showing off his acting chops. Watch this Funny Or Die video he did with Schumer, Apatow, and Hader on his pitch for a 'Trainwreck' sequel (that features a lot more of King James).SEE ALSO:Amy Schumer came up with the idea of "Trainwreck" during a very personal conversation with Judd ApatowMORE:Everything you missed from last night's athlete- and celebrity-filled ESPY AwardsJoin the conversation about this story Click here to read full news..