Few of the supporting roles were as important as the three members of Dewey’s band.

Chris Parnell (Theo): I got a call from Jake and Judd Apatow telling me about it and asking if I wanted to be a part of it. I couldn’t say no to something like that.

Matt Besser (Dave): I took guitar lessons when I was like 12. And I was terrible and I hated it. My teacher was old and we just played “Row, Row, Row Your Boat” and shit. But I’d always been a fan and hung out with guys in bands.

Tim Meadows (Sam): The preproduction work that they did on the movie was amazing. We learned how to play more songs than were in the movie. We had to learn everything that could possibly be coming our way.

Reilly: I just knew going in every day, “I’ve got this all-star comedy team around me.” So if I have to keep it serious one day, or I just don’t have any great ideas, these guys are just: boom boom boom. Every single day they’re coming up with new stuff and funny stuff.

Fischer: Me and Chris and Matt and Tim, we had a lot of free time on the set. We were like just sitting around in our full wardrobe waiting for our one hour of work each day. I just remember them making me laugh so hard.

Besser: When Judd gave us those roles, they gave us our instruments and teachers.

John Armentrout (music coach): They hired me to work with Matt Besser. He was struggling with guitar and needed some help.

Besser: I just would have nightmares of there being close shots on my fret work in the movie at some point. And of course, at best, they were 100 yards away from us playing guitar.

Armentrout: He grew to trust me and liked me and I guess he had talked to Chris Parnell on the set one day. … He had been taking lessons in New York on a regular electric bass and so Matt had told him about me and said, “Hey, maybe John can help you out.” So Chris called me and I started working with him.

Parnell: They gave me a bass that was marked with the frets, so I could figure out where to put my fingers more easily. And then they wrote it out in a way that would be easy to follow.

Armentrout: They made a last-minute change. They said, “In the ’50s-style stuff, we want you to play an upright bass because we just think the look would be better. It would be cool.” He was a little frustrated, and understandably so, because it was a completely foreign-looking instrument. And then he dove into it.

Parnell: I’m a little obsessive, so sometimes the track that we’d learn would change when we were actually shooting. Some little thing would be different, or maybe quite a bit different in the bass line, that would always drive me crazy. I would go, “What? That’s not what I learned.” I’m sure I was not a joy to deal with.

Armentrout: Look, I’m not an actor. I wasn’t gonna tell them how to act. I thought the only way I knew how to do this was to actually show them how to play the instruments and see how far they could take it.

Besser: The teachers would be like, “OK, this is the way they would strum in the late ’50s. And in the mid-’60s, they started strumming like this.” So it wasn’t just that we were learning how to play. We were learning how they would specifically do things in each era.

Meadows: I went in thinking my character is one of the best drummers in R&B or rock ’n’ roll. He had a reason for being around so long. Because the musicians were gonna stay throughout the whole span of the movie. So I was like, “This guy has gotta be good then.”

Besser: I think we stressed about it way too much. But the actual filming, when you’re there, is about the comedy, not, “Let’s hear Parnell, Meadows, and Matt Besser’s musicianship.”

Meadows: It’s the hardest work I ever did on a movie. I had to practice playing the drums. They had a set of electric drums set up in a room on the studio at the offices and I would go in on my days off and practice.

Parnell: It felt like getting to be a rock star for a little bit.

Meadows: Besser was actually strumming some of the chords correctly. But there were points where Besser couldn’t do it. He couldn’t strum it correctly. So he would turn to me like while we were playing so he would hide his fingering from the camera shot. And I would just shake my head, “No. You’re fucking horrible.” Like in character, though. He did it so much.

Besser: It was Chris, Tim, and I. We were a little trio. We became a band. When I think of that movie, I just think of the three of us, honestly.

Meadows: We ate our meals together every day on the set. And it was fun. There were running bits that we would do. We tried to make each other laugh. One I remember, we were doing that scene with Jack White, where we run off stage. We were just shooting the side where we all run off stage and as soon as we were out of camera frame, me and Besser would turn to Chris Parnell and pretend to kill him. We would mime it. I would hit him in the head with my drum sticks, and Matt would knee him in the stomach. And Chris would play along. He would bend over and then we would like, knock him to the floor and start kicking him in the face.

Armentrout: I told them that my one goal for them—aside from doing really well on camera—was I wanted them to play “Walk Hard” for me once as a group. Not to track or anything. And there was a point when we were down in San Pedro at the Warner Theatre where we were rehearsing and we kind of went through everything. We were talking about the punk version of “Walk Hard” and how we were gonna do that. And so I said, “Hey, we’ve got a few minutes to kill here.” And so I asked them—because they were kind of like, “We’re done, we want to get some lunch”—I said, “Can you do this for me?” And they’re like, “Yeah, sure we’ll do it.” They played through “Walk Hard,” start to finish, as a band. I’m not gonna say it was great or anything but it was pretty good. It made my day.