"A little Whiplash anecdote is, of course, like everybody else, I had no idea who Damien Chazelle was. Jason Reitman was the one who sent me the script, in an email, for Whiplash. He sent me both the short and the feature script and just said, “Read this,” and obviously it’s from Jason so I’m gonna read it. It was again, obviously, probably one of the most brilliant scripts I had ever read and one of the best fits in terms of the character that I really immediately understood and felt like I could wrap my brain around and pull off. They said, “The writer-director would love to meet you,” and we set up a lunch, and Damien and I sat down and immediately basically agreed on everything, except he didn’t know that I had a musical background, so he was talking about how we’d have body doubles and we’d have somebody coaching me on how to wave my arms around like a conductor. And I said, “Hey, we don’t need that because actually, that’s one of the arrows I have in my quiver.” That was one of those moments where it felt like kismet, that Damien was like, “Oh, my God.” He said, “When Jason and Helen suggested you for this part, I immediately thought that’s a great idea, but I had no idea that you actually had those kinds of abilities.” And also, he didn’t write the script for me, but he wrote it with Miles Teller in mind from the beginning, and didn’t know that Miles had been playing drums since he was 15 years old."

"My last two are gonna be Whiplash and Juno, for obvious reasons. [laughs] Juno came along, what is that, 10 years ago now? That came along when I had a nicely established career going and was paying my mortgage and putting my kids through their outrageous L.A. private school. We’d moved out from New York to L.A. two or three years before that, and I’d met Jason. I’d done Jason Reitman’s first feature, Thank You For Smoking, which is also an underrated film, by the way. Actually, he joined our semi-regular poker game when I was playing it at the time. And he quickly became, from a guy who basically barely knew what beats what in poker, he quickly became one of the best players at the table just because he’s such a smart guy. But we were playing at my friend’s house, and Jason showed up and he just handed me this paper script and he said, “Hey, I’m gonna be working on this,” or, “I just got this,” or something sort of vague, and he said, “You gotta read this. This is so good. It’s by this writer nobody ever heard of.” That night or the next day, I read the script, and of course immediately fell in love with the part of Juno’s dad, Mac MacGuff. You know, [Reitman] hadn’t said anything to me. He hadn’t said, “Look at this part,” or, “Look at that part.” So, I’m thinking, you know, maybe he wants me to play the drugstore guy in the first scene, or maybe he just wanted to share it with me because we’re pals now. I don’t know. It wasn’t until days later — and I wasn’t gonna say, “Hey, I wanna play this part” — it wasn’t until days later that he said, “Oh, God, of course, J.K. I want you to play the dad. Of course I do.” And he said, “I got the whole movie cast already in my head. I hope we get everybody I want.” Of course, the people financing the movie wanted him to get some famous pop star to play Juno, and they wanted to get some very well-known actor to play Juno’s dad. There were lists of guys that were way more famous than I was, but they kept throwing at Jason saying, “Look, if you want to get this movie made and get the budget that you want to have, these are the kind of guys that you need to play Juno’s dad.” For both Ellen Page and for me — and really for most of the characters, for Michael Cera, for Allison Janney — you know, these were all the people that he had in mind as soon as he read the script, but he knew he wanted the cast in the movie. He went to bat for all of us, and Ellen and I actually had to do a full on screen test that he set up with film, on actual film, at a sound stage. Jason had us do a couple scenes from the movie to convince the money people that we were the actors that were gonna help make the movie the best it could be. So that was a really nice vote of confidence from Jason, who, by the way, I just emailed five minutes before you called, because I’m gonna be doing his next movie, The Front Runner, which we start shooting in like less than two weeks."